Package 'PWEALL'

Title: Design and Monitoring of Survival Trials Accounting for Complex Situations
Description: Calculates various functions needed for design and monitoring survival trials accounting for complex situations such as delayed treatment effect, treatment crossover, non-uniform accrual, and different censoring distributions between groups. The event time distribution is assumed to be piecewise exponential (PWE) distribution and the entry time is assumed to be piecewise uniform distribution. As compared with Version 1.2.1, two more types of hybrid crossover are added. A bug is corrected in the function "pwecx" that calculates the crossover-adjusted survival, distribution, density, hazard and cumulative hazard functions. Also, to generate the crossover-adjusted event time random variable, a more efficient algorithm is used and the output includes crossover indicators.
Authors: Xiaodong Luo [aut, cre], Xuezhou Mao [ctb], Xun Chen [ctb], Hui Quan [ctb], Sanofi [cph]
Maintainer: Xiaodong Luo <[email protected]>
License: GPL (>= 2)
Version: 1.3.0.1
Built: 2024-11-04 06:27:22 UTC
Source: CRAN

Help Index


Design and Monitoring of Survival Trials Accounting for Complex Situations

Description

Calculates various functions needed for design and monitoring survival trials accounting for complex situations such as delayed treatment effect, treatment crossover, non-uniform accrual, and different censoring distributions between groups. The event time distribution is assumed to be piecewise exponential (PWE) distribution and the entry time is assumed to be piecewise uniform distribution. As compared with Version 1.2.1, two more types of hybrid crossover are added. A bug is corrected in the function "pwecx" that calculates the crossover-adjusted survival, distribution, density, hazard and cumulative hazard functions. Also, to generate the crossover-adjusted event time random variable, a more efficient algorithm is used and the output includes crossover indicators.

Details

The DESCRIPTION file:

Package: PWEALL
Type: Package
Version: 1.3.0.1
Date: 2018-10-18
Title: Design and Monitoring of Survival Trials Accounting for Complex Situations
Description: Calculates various functions needed for design and monitoring survival trials accounting for complex situations such as delayed treatment effect, treatment crossover, non-uniform accrual, and different censoring distributions between groups. The event time distribution is assumed to be piecewise exponential (PWE) distribution and the entry time is assumed to be piecewise uniform distribution. As compared with Version 1.2.1, two more types of hybrid crossover are added. A bug is corrected in the function "pwecx" that calculates the crossover-adjusted survival, distribution, density, hazard and cumulative hazard functions. Also, to generate the crossover-adjusted event time random variable, a more efficient algorithm is used and the output includes crossover indicators.
Authors@R: c( person(given="Xiaodong", family="Luo", email = "[email protected]", role =c("aut", "cre")), person(given="Xuezhou", family="Mao", role = "ctb"), person(given="Xun", family="Chen", role = "ctb"), person(given="Hui", family="Quan", role = "ctb"), person("Sanofi", role = "cph"))
Depends: R (>= 3.1.2)
Imports: survival, stats
License: GPL (>= 2)
RoxygenNote: 5.0.1
NeedsCompilation: yes
Packaged: 2023-08-09 04:22:22 UTC; ripley
Author: Xiaodong Luo [aut, cre], Xuezhou Mao [ctb], Xun Chen [ctb], Hui Quan [ctb], Sanofi [cph]
Maintainer: Xiaodong Luo <[email protected]>
Repository: CRAN
Date/Publication: 2023-08-09 04:33:51 UTC

Index of help topics:

PWEALL-package          Design and Monitoring of Survival Trials
                        Accounting for Complex Situations
cp                      Conditional power given observed log hazard
                        ratio
cpboundary              The stopping boundary based on the conditional
                        power criteria
cpstop                  The stopping probability based on the stopping
                        boundary
fourhr                  A utility functon
hxbeta                  A function to calculate the beta-smoothed
                        hazard rate
innercov                A utility function to calculate the inner
                        integration of the overall covariance
innervar                A utility function to calculate the inner
                        integration of the overall variance
instudyfindt            calculate the timeline in study when some or
                        all subjects have entered
ovbeta                  calculate the overall log hazard ratio
overallcov              calculate the overall covariance
overallcovp1            calculate the first part of the overall
                        covariance
overallcovp2            calculate the other parts of the overall
                        covariance
overallvar              calculate the overall variance
pwe                     Piecewise exponential distribution: hazard,
                        cumulative hazard, density, distribution,
                        survival
pwecx                   Various function for piecewise exponential
                        distribution with crossover effect
pwecxcens               Integration of the density of piecewise
                        exponential distribution with crossover effect
                        and the censoring function
pwecxpwu                Integration of the density of piecewise
                        exponential distribution with crossover effect,
                        censoring and recruitment function
pwecxpwufindt           calculate the timeline when certain number of
                        events accumulates
pwecxpwuforvar          calculate the utility function used for
                        varaince calculation
pwefv2                  A utility function
pwefvplus               A utility functon
pwepower                Calculating the powers of various the test
                        statistics for superiority trials
pwepowereq              Calculating the powers of various the test
                        statistics for equivalence trials
pwepowerfindt           Calculating the timepoint where a certain power
                        of the specified test statistics is obtained
pwepowerni              Calculating the powers of various the test
                        statistics for non-inferiority trials
pwesim                  simulating the test statistics
pwu                     Piecewise uniform distribution: distribution
qpwe                    Piecewise exponential distribution: quantile
                        function
qpwu                    Piecewise uniform distribution: quantile
                        function
rmstcov                 Calculation of the variance and covariance of
                        estimated restricted mean survival time
rmsth                   Estimate the restricted mean survival time
                        (RMST) and its variance from data
rmstpower               Calculate powers at different cut-points based
                        on difference of restricted mean survival times
                        (RMST)
rmstpowerfindt          Calculating the timepoint where a certain power
                        of mean difference of RMSTs is obtained
rmstsim                 simulating the restricted mean survival times
rmstutil                A utility function to calculate the true
                        restricted mean survival time (RMST) and its
                        variance account for delayed treatment,
                        discontinued treatment and non-uniform entry
rpwe                    Piecewise exponential distribution: random
                        number generation
rpwecx                  Piecewise exponential distribution with
                        crossover effect: random number generation
rpwu                    Piecewise uniform distribution: random number
                        generation
spf                     A utility function
wlrcal                  A utility function to calculate the weighted
                        log-rank statistics and their varainces given
                        the weights
wlrcom                  A function to calculate the various weighted
                        log-rank statistics and their varainces
wlrutil                 A utility function to calculate some common
                        functions in contructing weights

There are 5 types of crossover considered in the package: (1) Markov crossover, (2) Semi-Markov crosover, (3) Hybrid crossover-1, (4) Hybrid crossover-2 and (5) Hybrid crossover-3. The first 3 types are described in Luo et al. (2018). The fourth and fifth types are added for Version 1.3.0. The crossover type is determined by the hazard function after crossover λ2x(tu)\lambda_2^{\bf x}(t\mid u). For Type (1), the Markov crossover,

λ2x(tu)=λ2(t).\lambda_2^{\bf x}(t\mid u)=\lambda_2(t).

For Type (2), the Semi-Markov crossover,

λ2x(tu)=λ2(tu).\lambda_2^{\bf x}(t\mid u)=\lambda_2(t-u).

For Type (3), the hybrid crossover-1,

λ2x(tu)=π2λ2(tu)+(1π2)λ4(t).\lambda_2^{\bf x}(t\mid u)=\pi_2\lambda_2(t-u)+(1-\pi_2)\lambda_4(t).

For Type (4), the hazard after crossover is

λ2x(tu)=π2λ2(tu)S2(tu)+(1π2)λ4(t)S4(t)/S4(u)π2S2(tu)+(1π2)S4(t)/S4(u).\lambda_2^{\bf x}(t\mid u)=\frac{\pi_2\lambda_2(t-u)S_2(t-u)+(1-\pi_2)\lambda_4(t)S_4(t)/S_4(u)}{\pi_2 S_2(t-u)+(1-\pi_2)S_4(t)/S_4(u)}.

For Type (5), the hazard after crossover is

λ2x(tu)=π2λ2(tu)S2(tu)+(1π2)λ4(tu)S4(tu)π2S2(tu)+(1π2)S4(tu).\lambda_2^{\bf x}(t\mid u)=\frac{\pi_2\lambda_2(t-u)S_2(t-u)+(1-\pi_2)\lambda_4(t-u)S_4(t-u)}{\pi_2 S_2(t-u)+(1-\pi_2)S_4(t-u)}.

The types (4) and (5) are more closely related to "re-randomization", i.e. when a patient crosses, (s)he will have probability π2\pi_2 to have hazard λ2\lambda_2 and probability 1π21-\pi_2 to have hazard λ4\lambda_4. The types (4) and (5) differ in having λ4\lambda_4 as Markov or Semi-markov.

Author(s)

Xiaodong Luo [aut, cre], Xuezhou Mao [ctb], Xun Chen [ctb], Hui Quan [ctb], Sanofi [cph]

Maintainer: Xiaodong Luo <[email protected]>

References

Luo et al. (2018) Design and monitoring of survival trials in complex scenarios, Statistics in Medicine <doi: https://doi.org/10.1002/sim.7975>.


Conditional power given observed log hazard ratio

Description

This will calculate the conditional power given the observed log hazard ratio based on Cox model

Usage

cp(Dplan=300,alpha=0.05,two.sided=1,pi1=0.5,Obsbeta=log(seq(1,0.6,by=-0.01)),
   BetaD=log(0.8),Beta0=log(1),prop=seq(0.1,0.9,by=0.1))

Arguments

Dplan

Planned number of events at study end

alpha

Type 1 error rate

two.sided

=1 two-sided test and =0 one-sided test

pi1

Allocation probability for the treatment group

Obsbeta

observed log hazard ratio

BetaD

designed log hazard ratio, i.e. under alternative hypothesis

Beta0

null log hazard ratio, i.e. under null hypothesis

prop

proportion of Dplan observed

Details

This is to calculated conditional power at time point when certain percent of target number of event has been observed and an observed log hazard ratio is provided.

Value

CPT

Conditional power under current trend

CPN

Conditional power under null hypothesis

CPD

Conditional power according to design, i.e. under alternative hypothesis

Note

This will calculate the conditional power given the observed log hazard ratio based on Cox model

Author(s)

Xiaodong Luo

References

Halperin, Lan, Ware, Johnson and DeMets (1982). Controlled Clinical Trials.

See Also

cpboundary,cpstop

Examples

###Calculate the CP at 10-90 percent of the target 300 events when the observed HR 
###are seq(1,0.6,by=-0.01) with 2:1 allocation 
###ratio between the treatment group and the control group
cp(pi1=2/3)

The stopping boundary based on the conditional power criteria

Description

This will calculate the stopping boundary based on the conditional power criteria, i.e. if observed HR is above the boundary, the conditional power will be lower than the designated level. All the calculation is based on the proportional hazards assumption and the Cox model.

Usage

cpboundary(Dplan=300,alpha=0.05,two.sided=1,pi1=0.5,cpcut=c(0.2,0.3,0.4),
            BetaD=log(0.8),Beta0=log(1),prop=seq(0.1,0.9,by=0.1))

Arguments

Dplan

Planned number of events at study end

alpha

Type 1 error rate

two.sided

=1 two-sided test and =0 one-sided test

pi1

Allocation probability for the treatment group

cpcut

the designated conditional power level

BetaD

designed log hazard ratio, i.e. under alternative hypothesis

Beta0

null log hazard ratio, i.e. under null hypothesis

prop

proportion of Dplan observed

Details

This will calculate the stopping boundary based on the conditional power criteria, i.e. if observed HR is above the boundary, the conditional power will be lower than the designated level. All the calculation is based on the proportional hazards assumption and the Cox model.

Value

CPTbound

Boundary based on the conditional power under current trend

CPNbound

Boundary based on the conditional power under null hypothesis

CPDbound

Boundary based on the conditional power according to design, i.e. under alternative hypothesis

Note

This will calculate the stopping boundary based on the conditional power criteria

Author(s)

Xiaodong Luo

References

Halperin, Lan, Ware, Johnson and DeMets (1982). Controlled Clinical Trials.

See Also

cp,cpstop

Examples

###Calculate the stopping boundary at 10-90 percent of the target 300 events 
###when the condition power are c(0.2,0.3,0.4) with 
###2:1 allocation ratio between the treatment group and the control group
cpboundary(pi1=2/3)

The stopping probability based on the stopping boundary

Description

This will calculate the stopping probability given the stopping boundary. All the calculation is based on the proportional hazards assumption and the Cox model.

Usage

cpstop(Dplan=300,pi1=0.5,Beta1=log(0.8),Beta0=log(1),
        prop=seq(0.1,0.9,by=0.1),HRbound=rep(0.85,length(prop)))

Arguments

Dplan

Planned number of events at study end

pi1

Allocation probability for the treatment group

Beta1

designed log hazard ratio, i.e. under alternative hypothesis

Beta0

null log hazard ratio, i.e. under null hypothesis

prop

proportion of Dplan observed

HRbound

the stopping boundary

Details

This will calculate the stopping probability given the stopping boundary. All the calculation is based on the proportional hazards assumption and the Cox model.

Value

pstop0

Stopping probability under null hypothesis

pstop1

Stopping probability under alternative hypothesis

Note

This will calculate the stopping probability given the stopping boundary

Author(s)

Xiaodong Luo

References

Halperin, Lan, Ware, Johnson and DeMets (1982). Controlled Clinical Trials.

See Also

cp,cpboundary

Examples

###Calculate the stopping boundary at 10-90 percent of the target 300 events 
###when the condition power are c(0.2,0.3,0.4) with 2:1 allocation ratio 
###between the treatment group and the control group, we pick the boundary 
###based on 20 percent conditional power according to design, i.e. under alternative
targetD<-800 ###target number of events at study end
#############Allocation prob for the treatment group#############
pi1<-2/3
propevent<-seq(0.1,0.9,by=0.1) ###proportion of events at interim
HRbound<-cpboundary(Dplan=targetD,pi1=pi1,prop=propevent)$CPDbound[,1]  ###picking a boundary
pa<-cpstop(pi1=pi1,HRbound=HRbound)    ###stopping probabilities under null and alternative  
pa

###Calculate the stopping probability under non-constant hazard ratio
n1<-length(propevent)

####time point at which hazard rates and hazard ratios change
tchange<-c(0,6,12,24)                       
###annual event rates=0.09(1st yr), 0.07(2nd yr) and 0.05(2+yr) for control
ratet<-c(0.09/12,0.09/12,0.07/12,0.05/12)   
###annual censoring rate=0%(1st yr) and 1.5%(after) for control and treatment
ratec0<-c(0/12,0/12,0.015/12,0.015/12)      
ratec1<-ratec0                              
###annual treatment discontinuation rate=4% (1st yr) and 3% (after)
rate31<-c(0.04/12,0.04/12,0.03/12,0.03/12)  
rate30<-rep(0,length(tchange))              

############Recruitment curve##################
oa<-c(100,200,300,300,400,400,400,400,400,400,400,400,300,200)
ntotal<-sum(oa)
ntotal

taur<-length(oa)
ut<-seq(1,taur,by=1)
u<-oa/ntotal


#############Type-1 error rate#############
alpha<-0.05

####null hypothesis
eta0<-log(1)

####constant HR
etac<-log(0.8)

####non-constant HR
eta<-c(log(1),log(0.75),log(0.75),log(0.75)) ###6-m delayed 


####target number of events where calculations are performed##############
sevent<-propevent*targetD
nse<-length(sevent)
xtimeline<-xbeta<-xvar<-pxstop<-matrix(0,ncol=2,nrow=nse)
xtimeline[,1]<-xbeta[,1]<-xvar[,1]<-pxstop[,1]<-sevent
i<-1
tbegin<-proc.time()
for (i in 1:nse){
###find timeline
xtimeline[i,2]<-pwecxpwufindt(target=sevent[i],ntotal=ntotal,
                taur=taur,u=u,ut=ut,pi1=0.5,
                rate11=exp(eta)*ratet,rate21=exp(eta)*ratet,rate31=rate31,ratec1=ratec1,
                rate10=ratet,rate20=ratet,rate30=rate30,ratec0=ratec0,
                tchange=tchange,eps=0.001,init=taur,epsilon=0.000001,maxiter=100)$tau1

#Overall hazard ratio and varaince
xbeta[i,2]<-ovbeta(tfix=xtimeline[i,2],taur=taur,u=u,ut=ut,pi1=pi1,
                rate11=exp(eta)*ratet,rate21=exp(eta)*ratet,rate31=rate31,ratec1=ratec1,
                rate10=ratet,rate20=ratet,rate30=rate30,ratec0=ratec0,
                tchange=tchange,eps=0.001,veps=0.001,epsbeta=1.0e-10)$b1
xvar[i,2]<-overallvar(tfix=xtimeline[i,2],taur=taur,u=u,ut=ut,pi1=pi1,
                rate11=exp(eta)*ratet,rate21=exp(eta)*ratet,rate31=rate31,ratec1=ratec1,
                rate10=ratet,rate20=ratet,rate30=rate30,ratec0=ratec0,
                tchange=tchange,eps=0.001,veps=0.001,beta=xbeta[i,2])$vbeta
}
##stopping prob
pxstop[,2]<-1-pnorm(sqrt(ntotal)*(log(HRbound)-xbeta[,2])/sqrt(xvar[,2]))
tend<-proc.time()

xout<-cbind(xtimeline[,1],xtimeline[,2],xbeta[,2],xvar[,2]/ntotal,
            1/pi1/(1-pi1)/xtimeline[,1],pxstop[,2],pa$pstop0,pa$pstop1)
xnames<-c("# of events", "Time", "Estbeta", "TrueV", "ApproxV", "NCHR", "Null", "CHR")
colnames(xout)<-xnames
options(digits=2)
xout

A utility functon

Description

This will calculate the more complex integration

Usage

fourhr(t=seq(0,5,by=0.5),rate1=c(0,5,0.8),rate2=rate1,
                   rate3=c(0.1,0.2),rate4=rate2,tchange=c(0,3),eps=1.0e-2)

Arguments

t

A vector of time points

rate1

piecewise constant event rate

rate2

piecewise constant event rate

rate3

piecewise constant event rate

rate4

additional piecewise constant

tchange

a strictly increasing sequence of time points starting from zero at which event rate changes. The first element of tchange must be zero. The above rates and tchange must have the same length.

eps

tolerance

Details

Let h1,,h4h_1,\ldots,h_4 correspond to rate1,...,rate4, and H1,,H4H_1,\ldots,H_4 be the corresponding survival functions. We calculate

0th1(s)H2(s)h3(ts)H4(ts)ds.\int_0^t h_1(s)H_2(s)h_3(t-s)H_4(t-s)ds.

Value

fx

values

Note

This provides the result of the complex integration

Author(s)

Xiaodong Luo

References

Luo et al. (2018) Design and monitoring of survival trials in complex scenarios, Statistics in Medicine <doi: https://doi.org/10.1002/sim.7975>.

See Also

rpwe

Examples

r1<-c(0.6,0.3)
r2<-c(0.6,0.6)
r3<-c(0.1,0.2)
r4<-c(0.5,0.4)
tchange<-c(0,1.75)
fourhrfun<-fourhr(t=seq(0,5,by=0.5),rate1=r1,rate2=r2,rate3=r3,
                 rate4=r4,tchange=c(0,3),eps=1.0e-2)
fourhrfun

A function to calculate the beta-smoothed hazard rate

Description

A function to calculate the beta-smoothed hazard rate

Usage

hxbeta(x=c(0.5,1),y=seq(.1,1,by=0.01),d=rep(1,length(y)),
           tfix=2,K=20,eps=1.0e-06)

Arguments

x

time points where the estimated hazards are calculated

y

observed times

d

non-censoring indicators

tfix

maximum time point at which the hazard function is estimated

K

smooth parameter for the hazard estimate

eps

the error tolerance when comparing event times

Details

V1:3/21/2018

Value

lambda

estimated hazard at points x

Author(s)

Xiaodong Luo

Examples

n<-200
taur<-2.8
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
tfix<-taur+2
tseq<-seq(0,tfix,by=0.1)
r11<-c(1,0.5)
r21<-c(0.5,0.8)
r31<-c(0.7,0.4)
r41<-r51<-r21
rc1<-c(0.5,0.6)
tchange<-c(0,1.873)

E<-T<-C<-d<-rep(0,n)
E<-rpwu(nr=n,u=u,ut=ut)$r
C<-rpwe(nr=n,rate=rc1,tchange=tchange)$r
T<-rpwecx(nr=n,rate1=r11,rate2=r21,rate3=r31,
               rate4=r41,rate5=r51,tchange=tchange,type=1)$r
y<-pmin(pmin(T,C),tfix-E)
y1<-pmin(C,tfix-E)
d[T<=y]<-1

lambda=hxbeta(x=tseq,y=y,d=d,tfix=tfix,K=20,eps=1.0e-06)$lambda
lambda

A utility function to calculate the inner integration of the overall covariance

Description

This will calculate the inner integration of the overall covariance accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

innercov(tupp=seq(0,10,by=0.5),tlow=tupp-0.1,taur=5,
                   u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
                   rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),
                   rate41=rate21,rate51=rate21,ratec1=c(0.5,0.6),
                   rate10=rate11,rate20=rate10,rate30=rate31,
                   rate40=rate20,rate50=rate20,ratec0=ratec1,
                   tchange=c(0,1),type1=1,type0=1,
                   rp21=0.5,rp20=0.5,
                   eps=1.0e-2,veps=1.0e-2,beta=0)

Arguments

tupp

A vector of upper bounds

tlow

A vector of lower bounds

taur

recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob for the treatment group

rp20

re-randomization prob for the control group

eps

A small number representing the error tolerance when calculating the utility function

Φl(x)=0xslesdsxl+1\Phi_l(x)=\frac{\int_0^x s^l e^{-s}ds}{x^{l+1}}

with l=0,1,2l=0,1,2.

veps

A small number representing the error tolerance when calculating the integrations.

beta

The value at which the inner part of the covaraince is computed.

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

qf1

The first part of the inner integration

qf2

The second part of the inner integration

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo et al. (2018) Design and monitoring of survival trials in complex scenarios, Statistics in Medicine <doi: https://doi.org/10.1002/sim.7975>.

See Also

pwe,rpwe,qpwe,pwecx,ovbeta,innervar

Examples

taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(1,0.5)
r21<-c(0.5,0.8)
r31<-c(0.7,0.4)
r41<-r51<-r21
rc1<-c(0.5,0.6)
r10<-c(1,0.7)
r20<-c(0.5,1)
r30<-c(0.3,0.4)
r40<-r50<-r20
rc0<-c(0.2,0.4)
getinner<-innercov(tupp=rep(5,times=11),tlow=seq(0,5,by=0.5),taur=taur,u=u,ut=ut,pi1=0.5,
                     rate11=r11,rate21=r21,rate31=r31,
                     rate41=r41,rate51=r51,ratec1=rc1,
                     rate10=r10,rate20=r20,rate30=r30,
                     rate40=r40,rate50=r50,ratec0=rc0,
                     tchange=c(0,1),type1=1,type0=1,
                     eps=1.0e-2,veps=1.0e-2,beta=0.5)
cbind(getinner$qf1,getinner$qf0)

A utility function to calculate the inner integration of the overall variance

Description

This will calculate the inner integration of the overall variance accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

innervar(t=seq(0,10,by=0.5),taur=5,u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
                     rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),
                     rate41=rate21,rate51=rate21,ratec1=c(0.5,0.6),
                     rate10=rate11,rate20=rate10,rate30=rate31,
                     rate40=rate20,rate50=rate20,ratec0=c(0.6,0.5),
                     tchange=c(0,1),type1=1,type0=1,
                     rp21=0.5,rp20=0.5,
                     eps=1.0e-2,veps=1.0e-2,beta=0)

Arguments

t

A vector of time points where the integration is calculated.

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob for the treatment group

rp20

re-randomization prob for the control group

eps

A small number representing the error tolerance when calculating the utility function

Φl(x)=0xslesdsxl+1\Phi_l(x)=\frac{\int_0^x s^l e^{-s}ds}{x^{l+1}}

with l=0,1,2l=0,1,2.

veps

A small number representing the error tolerance when calculating the Fisher information.

beta

The value at which the varaince is computed.

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

qf1

The first part of the inner integration

qf2

The second part of the inner integration

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo et al. (2018) Design and monitoring of survival trials in complex scenarios, Statistics in Medicine <doi: https://doi.org/10.1002/sim.7975>.

See Also

pwe,rpwe,qpwe,pwecx,ovbeta,innervar

Examples

taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(1,0.5)
r21<-c(0.5,0.8)
r31<-c(0.7,0.4)
r41<-r51<-r21
rc1<-c(0.5,0.6)
r10<-c(1,0.7)
r20<-c(0.5,1)
r30<-c(0.3,0.4)
r40<-r50<-r20
rc0<-c(0.2,0.4)
getinner<-innervar(t=seq(0,10,by=0.5),taur=taur,u=u,ut=ut,pi1=0.5,
                     rate11=r11,rate21=r21,rate31=r31,
                     rate41=r41,rate51=r51,ratec1=rc1,
                     rate10=r10,rate20=r20,rate30=r30,
                     rate40=r40,rate50=r50,ratec0=rc0,
                     tchange=c(0,1),type1=1,type0=1,
                     eps=1.0e-2,veps=1.0e-2,beta=0.5)
cbind(getinner$qf1,getinner$qf0)

calculate the timeline in study when some or all subjects have entered

Description

This will calculate the timeline from some timepoint in study when some/all subjects have entered accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

instudyfindt(target=400,y=exp(rnorm(300)),z=rbinom(300,1,0.5),
                  d=rep(c(0,1,2),each=100),
                  tcut=2,blinded=1,type0=1,type1=type0,
                  rp20=0.5,rp21=0.5,tchange=c(0,1),
                  rate10=c(1,0.7),rate20=c(0.9,0.7),rate30=c(0.4,0.6),rate40=rate20,
                  rate50=rate20,ratec0=c(0.3,0.3),
                  rate11=rate10,rate21=rate20,rate31=rate30,
                  rate41=rate40,rate51=rate50,ratec1=ratec0,
                  withmorerec=1,
                  ntotal=1000,taur=5,u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
                  ntype0=1,ntype1=1,
                  nrp20=0.5,nrp21=0.5,ntchange=c(0,1),
                  nrate10=rate10,nrate20=rate20,nrate30=rate30,nrate40=rate40,
                  nrate50=rate50,nratec0=ratec0,
                  nrate11=rate10,nrate21=rate20,nrate31=rate30,nrate41=rate40,
                  nrate51=rate50,nratec1=ratec0,
                  eps=1.0e-2,init=tcut*1.1,epsilon=0.001,maxiter=100)

Arguments

target

target number of events

y

observed times

z

observed treatment indicator when blinded=0, z=1 denotes the treatment group and 0 the control group

d

event indicator, 1=event, 0=censored, 2=no event or censored up to tcut, the data cut-point

tcut

the data cut-point

blinded

blinded=1 if the data is blinded,=0 if it is unblinded

type0

type of the crossover for the observed data in the control group

type1

type of the crossover for the observed data in the treatment group

rp20

re-randomization prob for the observed data in the control group

rp21

re-randomization prob for the observed data in the treatment group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as ratejk, j=1,2,3,4,5,c; k=0,1

rate10

Hazard before crossover for the old subjects in the control group

rate20

Hazard after crossover for the old subjects in the control group

rate30

Hazard for time to crossover for the old subjects in the control group

rate40

Hazard after crossover for the old subjects in the control group for complex case

rate50

Hazard after crossover for the old subjects in the control group for complex case

ratec0

Hazard for time to censoring for the old subjects in the control group

rate11

Hazard before crossover for the old subjects in the treatment group

rate21

Hazard after crossover for the old subjects in the treatment group

rate31

Hazard for time to crossover for the old subjects in the treatment group

rate41

Hazard after crossover for the old subjects in the treatment group for complex case

rate51

Hazard after crossover for the old subjects in the treatment group for complex case

ratec1

Hazard for time to censoring for the old subjects in the treatment group

withmorerec

withmorerec=1 if more subjects are needed to be recruited; =0 otherwise

ntotal

total number of the potential new subjects

taur

recruitment time for the potential new subjects

u

Piecewise constant recuitment rate for the potential new subjects

ut

Recruitment intervals for the potential new subjects

pi1

Allocation probability to the treatment group for the potential new subjects

ntype0

type of the crossover for the potential new subjects in the control group

ntype1

type of the crossover for the potential new subjects in the treatment group

nrp20

re-randomization prob for the potential new subjects in the control group

nrp21

re-randomization prob for the potential new subjects in the treatment group

ntchange

A strictly increasing sequence of time points at which the event rates changes. The first element of ntchange must be zero. It must have the same length as nratejk, j=1,2,3,4,5,c; k=0,1

nrate10

Hazard before crossover for the potential new subjects in the control group

nrate20

Hazard after crossover for the potential new subjects in the control group

nrate30

Hazard for time to crossover for the potential new subjects in the control group

nrate40

Hazard after crossover for the potential new subjects in the control group for complex case

nrate50

Hazard after crossover for the potential new subjects in the control group for complex case

nratec0

Hazard for time to censoring for the potential new subjects in the control group

nrate11

Hazard before crossover for the potential new subjects in the treatment group

nrate21

Hazard after crossover for the potential new subjects in the treatment group

nrate31

Hazard for time to crossover for the potential new subjects in the treatment group

nrate41

Hazard after crossover for the potential new subjects in the treatment group for complex case

nrate51

Hazard after crossover for the potential new subjects in the treatment group for complex case

nratec1

Hazard for time to censoring for the potential new subjects in the treatment group

eps

A small number representing the error tolerance when calculating the utility function

Φl(x)=0xslesdsxl+1\Phi_l(x)=\frac{\int_0^x s^l e^{-s}ds}{x^{l+1}}

with l=0,1,2l=0,1,2.

init

initital value of the timeline estimate

epsilon

A small number representing the error tolerance when calculating the timeline.

maxiter

Maximum number of iterations when calculating the timeline

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange. The hazard functions corresponding to nrate11,...,nrate51,nratec1, nrate10,...,nrate50,nratec0 are all piecewise constant functions and all must have the same ntchange.

Value

t1

the calculated timeline

dvalue

the number of events

dvprime

the derivative of the event cummulative function at time t1

tvar

the variance of the timeline estimator

ny

total number of subjects that could be in the study

eps

final tolerance

iter

Number of iterations performed

t1hist

the history of the iteration for timeline

dvaluehist

the history of the iteration for the event count

dvprimehist

the history of the iteration for the derivative of event count with respect to time

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

pwe,rpwe,qpwe,pwecxpwufindt

Examples

n<-1000
target<-550
ntotal<-1000
pi1<-0.5
taur<-2.8
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(1,0.5)
r21<-c(0.5,0.8)
r31<-c(0.7,0.4)
r41<-r51<-r21
rc1<-c(0.5,0.6)
r10<-c(1,0.7)
r20<-c(0.5,1)
r30<-c(0.3,0.4)
r40<-r50<-r20
rc0<-c(0.2,0.4)
tchange<-c(0,1.873)
tcut<-2

####generate the data
E<-T<-C<-Z<-delta<-rep(0,n)
E<-rpwu(nr=n,u=u,ut=ut)$r
Z<-rbinom(n,1,pi1)
n1<-sum(Z)
n0<-sum(1-Z)
C[Z==1]<-rpwe(nr=n1,rate=rc1,tchange=tchange)$r
C[Z==0]<-rpwe(nr=n0,rate=rc0,tchange=tchange)$r
T[Z==1]<-rpwecx(nr=n1,rate1=r11,rate2=r21,rate3=r31,
                rate4=r41,rate5=r51,tchange=tchange,type=1)$r
T[Z==0]<-rpwecx(nr=n0,rate1=r10,rate2=r20,rate3=r30,
                rate4=r40,rate5=r50,tchange=tchange,type=1)$r
y<-pmin(pmin(T,C),tcut-E)
y1<-pmin(C,tcut-E)
delta[T<=y]<-1
delta[C<=y]<-0
delta[tcut-E<=y & tcut-E>0]<-2
delta[tcut-E<=y & tcut-E<=0]<--1

ys<-y[delta>-1]
Zs<-Z[delta>-1]
ds<-delta[delta>-1]

nplus<-sum(delta==-1)
nd0<-sum(ds==0)
nd1<-sum(ds==1)
nd2<-sum(ds==2)


ntaur<-taur-tcut
nu<-c(1/ntaur,1/ntaur)
nut<-c(ntaur/2,ntaur)

###calculate the timeline at baseline
xt<-pwecxpwufindt(target=target,ntotal=n,taur=taur,u=u,ut=ut,pi1=pi1,
              rate11=r11,rate21=r21,rate31=r31,ratec1=rc1,
              rate10=r10,rate20=r20,rate30=r30,ratec0=rc0,
              tchange=tchange,eps=0.001,init=taur,epsilon=0.000001,maxiter=100)
###calculate the timeline in study
yt<-instudyfindt(target=target,y=ys,z=Zs,d=ds,
                       tcut=tcut,blinded=0,type1=1,type0=1,tchange=tchange,
                       rate10=r10,rate20=r20,rate30=r30,ratec0=rc0,
                       rate11=r11,rate21=r21,rate31=r31,ratec1=rc1,
                       withmorerec=1,
                       ntotal=nplus,taur=ntaur,u=nu,ut=nut,pi1=pi1,
                       ntype1=1,ntype0=1,ntchange=tchange,
                       nrate10=r10,nrate20=r20,nrate30=r30,nratec0=rc0,
                       nrate11=r11,nrate21=r21,nrate31=r31,nratec1=rc1,
                       eps=1.0e-2,init=2,epsilon=0.001,maxiter=100)
##timelines                       
c(yt$t1,xt$t1)
##standard errors of the timeline estimators 
c(sqrt(yt$tvar/yt$ny),sqrt(xt$tvar/n))
###95 percent CIs
c(yt$t1-1.96*sqrt(yt$tvar/yt$ny),yt$t1+1.96*sqrt(yt$tvar/yt$ny))
c(xt$t1-1.96*sqrt(xt$tvar/n),xt$t1+1.96*sqrt(xt$tvar/n))

calculate the overall log hazard ratio

Description

This will calculate the overall (log) hazard ratio accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

ovbeta(tfix=2.0,taur=5,u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
       rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),rate41=rate21,
       rate51=rate21,ratec1=c(0.5,0.6),
       rate10=rate11,rate20=rate10,rate30=rate31,rate40=rate20,
       rate50=rate20,ratec0=c(0.4,0.3),
       tchange=c(0,1),type1=1,type0=1,
       rp21=0.5,rp20=0.5,
       eps=1.0e-2,veps=1.0e-2,
       beta0=0,epsbeta=1.0e-4,iterbeta=25)

Arguments

tfix

The time point where the overall log hazard ratio is computed.

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob in the treatment group

rp20

re-randomization prob in the control group

eps

A small number representing the error tolerance when calculating the utility function

Φl(x)=0xslesdsxl+1\Phi_l(x)=\frac{\int_0^x s^l e^{-s}ds}{x^{l+1}}

with l=0,1,2l=0,1,2.

veps

A small number representing the error tolerance when calculating the Fisher information.

beta0

The starting value of the Newton-Raphson iterative procedure.

epsbeta

Absolute tolerance when calculating the overall log hazard ratio.

iterbeta

Maximum number of iterations when calculating the overall log hazard ratio.

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

b1

The overall log hazard ratio

hr

The overall hazard ratio

err

Error at the last iterative step

iter

Number of iterations performed

bhist

The overall log hazard ratio at each step

xnum

The expected score function at each step

xdenom

The Fisher information at each step

atsupp

The grids used to cut the interval [0,tfix] in order to approximate the Fisher information

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

pwe,rpwe,qpwe

Examples

taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(1,0.5)
r21<-c(0.5,0.8)
r31<-c(0.7,0.4)
r41<-r51<-r21
rc1<-c(0.5,0.6)
r10<-c(1,0.7)
r20<-c(0.5,1)
r30<-c(0.3,0.4)
r40<-r50<-r20
rc0<-c(0.2,0.4)
getbeta<-ovbeta(tfix=2.0,taur=taur,u=u,ut=ut,pi1=0.5,
       rate11=r11,rate21=r21,rate31=r31,rate41=r41,rate51=r51,ratec1=rc1,
       rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
       tchange=c(0,1),type1=1,type0=1,eps=1.0e-2,veps=1.0e-2,beta0=0,epsbeta=1.0e-4,iterbeta=25)
getbeta$b1

calculate the overall covariance

Description

This will calculate the overall covariance accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

overallcov(tfix=2.0,tfix0=1.0,taur=5,u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
              rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),
              rate41=rate21,rate51=rate21,ratec1=c(0.5,0.6),
              rate10=c(1,0.7),rate20=rate10,rate30=rate31,
              rate40=rate20,rate50=rate20,ratec0=ratec1,
              tchange=c(0,1),type1=1,type0=1,
              rp21=0.5,rp20=0.5,
              eps=1.0e-2,veps=1.0e-2,beta=0,beta0=0)

Arguments

tfix

The upper point where the overall covariance is computed.

tfix0

The lower point where the overall covariance is computed.

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob in the treatment group

rp20

re-randomization prob in the control group

eps

A small number representing the error tolerance when calculating the utility function

Φl(x)=0xslesdsxl+1\Phi_l(x)=\frac{\int_0^x s^l e^{-s}ds}{x^{l+1}}

with l=0,1,2l=0,1,2.

veps

A small number representing the error tolerance when calculating the Fisher information.

beta

The value at which the covaraince is computed, upper bound

beta0

The value at which the covaraince is computed, lower bound

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

covbeta

The covariance the score functions

covbeta1

The first part of the cov

covbeta2

The second part of the cov

covbeta3

The third part of the cov

covbeta4

The fourth part of the cov

EA1

The first score function

EA2

The second score function

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

pwe,rpwe,qpwe,ovbeta,innervar

Examples

taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(1,0.5)
r21<-c(0.5,0.8)
r31<-c(0.7,0.4)
r41<-r51<-r21
rc1<-c(0.5,0.6)
r10<-c(1,0.7)
r20<-c(0.5,1)
r30<-c(0.3,0.4)
r40<-r50<-r20
rc0<-c(0.2,0.4)
getcov<-overallcov(tfix=2.0,tfix0=1.0,taur=taur,u=u,ut=ut,pi1=0.5,
              rate11=r11,rate21=r21,rate31=r31,
              rate41=r41,rate51=r51,ratec1=rc1,
              rate10=r10,rate20=r20,rate30=r30,
              rate40=r40,rate50=r50,ratec0=rc0,
              tchange=c(0,1),type1=1,type0=1,
              eps=1.0e-2,veps=1.0e-2,beta=0,beta0=0)
getcov$covbeta

calculate the first part of the overall covariance

Description

This will calculate the first part of the overall covariance accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

overallcovp1(tfix=2.0,tfix0=1.0,taur=5,u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
                    rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),
                    rate41=rate21,rate51=rate51,ratec1=c(0.5,0.6),
                    rate10=rate11,rate20=rate10,rate30=rate31,
                    rate40=rate20,rate50=rate20,ratec0=ratec1,
                    tchange=c(0,1),type1=1,type0=1,
                    rp21=0.5,rp20=0.5,
                    eps=1.0e-2,veps=1.0e-2,beta=0,beta0=0)

Arguments

tfix

The upper point where the overall covariance is computed.

tfix0

The lower point where the overall covariance is computed.

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob in the treatment group

rp20

re-randomization prob in the control group

eps

A small number representing the error tolerance when calculating the utility function

Φl(x)=0xslesdsxl+1\Phi_l(x)=\frac{\int_0^x s^l e^{-s}ds}{x^{l+1}}

with l=0,1,2l=0,1,2.

veps

A small number representing the error tolerance when calculating the Fisher information.

beta

The value at which the covaraince is computed, upper bound

beta0

The value at which the covaraince is computed, lower bound

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

covbeta1

The first part of the covariance

EA1

The first score function

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

pwe,rpwe,qpwe,ovbeta,innervar

Examples

taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(1,0.5)
r21<-c(0.5,0.8)
r31<-c(0.7,0.4)
r41<-r51<-r21
rc1<-c(0.5,0.6)
r10<-c(1,0.7)
r20<-c(0.5,1)
r30<-c(0.3,0.4)
r40<-r50<-r20
rc0<-c(0.2,0.4)
getcov1<-overallcovp1(tfix=2.0,tfix0=1.0,taur=taur,u=u,ut=ut,pi1=0.5,
              rate11=r11,rate21=r21,rate31=r31,
              rate41=r41,rate51=r51,ratec1=rc1,
              rate10=r10,rate20=r20,rate30=r30,
              rate40=r40,rate50=r50,ratec0=rc0,
              tchange=c(0,1),type1=1,type0=1,
              eps=1.0e-2,veps=1.0e-2,beta=0,beta0=0)
getcov1$covbeta1

calculate the other parts of the overall covariance

Description

This will calculate the other parts of the overall covariance accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

overallcovp2(tfix=2.0,tfix0=1.0,taur=5,u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
                    rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),
                    rate41=rate21,rate51=rate51,ratec1=c(0.5,0.6),
                    rate10=rate11,rate20=rate10,rate30=rate31,
                    rate40=rate20,rate50=rate20,ratec0=ratec1,
                    tchange=c(0,1),type1=1,type0=1,
                    rp21=0.5,rp20=0.5,
                    eps=1.0e-2,veps=1.0e-2,beta=0,beta0=0)

Arguments

tfix

The upper point where the overall covariance is computed.

tfix0

The lower point where the overall covariance is computed.

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob in the treatment group

rp20

re-randomization prob in the control group

eps

A small number representing the error tolerance when calculating the utility function

Φl(x)=0xslesdsxl+1\Phi_l(x)=\frac{\int_0^x s^l e^{-s}ds}{x^{l+1}}

with l=0,1,2l=0,1,2.

veps

A small number representing the error tolerance when calculating the Fisher information.

beta

The value at which the covaraince is computed, upper bound

beta0

The value at which the covaraince is computed, lower bound

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

cov234

The other part of the covariance

covbeta2

The second part of the covariance

covbeta3

The third part of the covariance

covbeta4

The fourth part of the covariance

EA2

The second score function

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

pwe,rpwe,qpwe,ovbeta,innervar

Examples

taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(1,0.5)
r21<-c(0.5,0.8)
r31<-c(0.7,0.4)
r41<-r51<-r21
rc1<-c(0.5,0.6)
r10<-c(1,0.7)
r20<-c(0.5,1)
r30<-c(0.3,0.4)
r40<-r50<-r20
rc0<-c(0.2,0.4)
getcov2<-overallcovp2(tfix=2.0,tfix0=1.0,taur=taur,u=u,ut=ut,pi1=0.5,
              rate11=r11,rate21=r21,rate31=r31,
              rate41=r41,rate51=r51,ratec1=rc1,
              rate10=r10,rate20=r20,rate30=r30,
              rate40=r40,rate50=r50,ratec0=rc0,
              tchange=c(0,1),type1=1,type0=1,
              eps=1.0e-2,veps=1.0e-2,beta=0,beta0=0)
getcov2

calculate the overall variance

Description

This will calculate the overall variance accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

overallvar(tfix=2.0,taur=5,u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
                     rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),
                     rate41=rate21,rate51=rate21,ratec1=c(0.5,0.6),
                     rate10=rate11,rate20=rate10,rate30=rate31,
                     rate40=rate20,rate50=rate20,ratec0=c(0.6,0.5),
                     tchange=c(0,1),type1=1,type0=1,
                     rp21=0.5,rp20=0.5,
                     eps=1.0e-2,veps=1.0e-2,beta=0)

Arguments

tfix

The time point where the overall variance is computed.

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob in the treatment group

rp20

re-randomization prob in the control group

eps

A small number representing the error tolerance when calculating the utility function

Φl(x)=0xslesdsxl+1\Phi_l(x)=\frac{\int_0^x s^l e^{-s}ds}{x^{l+1}}

with l=0,1,2l=0,1,2.

veps

A small number representing the error tolerance when calculating the Fisher information.

beta

The value at which the varaince is computed.

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

vbeta

The variance of the overall log hazard ratio at the specified beta

vs

The variance of the score function at the specified beta

xdenom

Fisher information at the specified beta

EA

value of the score function

EA2

The first part of the variance

AB

Half of the second part of the variance

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

pwe,rpwe,qpwe,ovbeta,innervar

Examples

taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(1,0.5)
r21<-c(0.5,0.8)
r31<-c(0.7,0.4)
r41<-r51<-r21
rc1<-c(0.5,0.6)
r10<-c(1,0.7)
r20<-c(0.5,1)
r30<-c(0.3,0.4)
r40<-r50<-r20
rc0<-c(0.2,0.4)
###variance with beta=0, calculate log-rank variance under the alternative
vbeta0<-overallvar(tfix=2.0,taur=taur,u=u,ut=ut,pi1=0.5,
        rate11=r11,rate21=r21,rate31=r31,rate41=r41,rate51=r51,ratec1=rc1,
        rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
        tchange=c(0,1),type1=1,type0=1,eps=1.0e-2,veps=1.0e-2,beta=0)

###variance with beta=0, calculate log-rank variance under the alternative
###Estimate the overall beta
getbeta<-ovbeta(tfix=2.0,taur=taur,u=u,ut=ut,pi1=0.5,
        rate11=r11,rate21=r21,rate31=r31,rate41=r41,rate51=r51,ratec1=rc1,
        rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
        tchange=c(0,1),type1=1,type0=1,eps=1.0e-2,veps=1.0e-2,beta0=0,
        epsbeta=1.0e-4,iterbeta=25)
vbeta<-overallvar(tfix=2.0,taur=taur,u=u,ut=ut,pi1=0.5,
        rate11=r11,rate21=r21,rate31=r31,rate41=r41,rate51=r51,ratec1=rc1,
        rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
      tchange=c(0,1),type1=1,type0=1,eps=1.0e-2,veps=1.0e-2,beta=getbeta$b1)
cbind(vbeta0$vs,vbeta$vs)

Piecewise exponential distribution: hazard, cumulative hazard, density, distribution, survival

Description

This will provide the related functions of the specified piecewise exponential distribution.

Usage

pwe(t=seq(0,5,by=0.5),rate=c(0,5,0.8),tchange=c(0,3))

Arguments

t

A vector of time points.

rate

A vector of event rates

tchange

A strictly increasing sequence of time points at which the event rate changes. The first element of tchange must be zero. It must have the same length as rate.

Details

Let λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j) be the hazard function, where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of rate and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. The cumulative hazard function

Λ(t)=j=1mλj(ttjttj1),\Lambda(t)=\sum_{j=1}^m \lambda_j(t\wedge t_j-t\wedge t_{j-1}),

the survival function S(t)=exp{Λ(t)}S(t)=\exp\{-\Lambda(t)\}, the distribution function F(t)=1S(t)F(t)=1-S(t) and the density function f(t)=λ(t)S(t)f(t)=\lambda(t)S(t).

Value

hazard

Hazard function

cumhazard

Cumulative hazard function

density

Density function

dist

Distribution function

surv

Survival function

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

rpwe,qpwe

Examples

t<-seq(0,3,by=0.1)
rate<-c(0.6,0.3)
tchange<-c(0,1.75)
pwefun<-pwe(t=t,rate=rate,tchange=tchange)
pwefun

Various function for piecewise exponential distribution with crossover effect

Description

This will calculate the functions according to the piecewise exponential distribution with crossover

Usage

pwecx(t=seq(0,10,by=0.5),rate1=c(1,0.5),rate2=rate1,rate3=c(0.7,0.4),
      rate4=rate2,rate5=rate2,tchange=c(0,1),type=1,rp2=0.5,eps=1.0e-2)

Arguments

t

a vector of time points

rate1

piecewise constant event rate before crossover

rate2

piecewise constant event rate after crossover

rate3

piecewise constant event rate for crossover

rate4

additional piecewise constant event rate for more complex crossover

rate5

additional piecewise constant event rate for more complex crossover

tchange

a strictly increasing sequence of time points starting from zero at which event rate changes. The first element of tchange must be zero. The above rates rate1 to rate5 and tchange must have the same length.

type

type of crossover, i.e. 1: markov, 2: semi-markov, 3: hybrid case 1(as indicated in the reference), 4: hybrid case 2, 5: hybrid case 3.

rp2

re-randomization prob

eps

tolerance

Details

More details

Value

hazard

Hazard function

cumhazard

Cumulative hazard function

density

Density function

dist

Distribution function

surv

Survival function

Note

This provides a random number generator of the piecewise exponetial distribution with crossover

Author(s)

Xiaodong Luo

References

Luo et al. (2018) Design and monitoring of survival trials in complex scenarios, Statistics in Medicine <doi: https://doi.org/10.1002/sim.7975>.

See Also

rpwe

Examples

r1<-c(0.6,0.3)
r2<-c(0.6,0.6)
r3<-c(0.1,0.2)
r4<-c(0.5,0.4)
r5<-c(0.4,0.5)
pwecxfun<-pwecx(t=seq(0,10,by=0.5),rate1=r1,rate2=r2,rate3=r3,rate4=r4,
                rate5=r5,tchange=c(0,1),type=1,eps=1.0e-2)
pwecxfun$surv

Integration of the density of piecewise exponential distribution with crossover effect and the censoring function

Description

This will calculate the functions according to the piecewise exponential distribution with crossover

Usage

pwecxcens(t=seq(0,10,by=0.5),rate1=c(1,0.5),rate2=rate1,
                rate3=c(0.7,0.4),rate4=rate2,rate5=rate2,ratec=c(0.2,0.3),
                tchange=c(0,1),type=1,rp2=0.5,eps=1.0e-2)

Arguments

t

a vector of time points

rate1

piecewise constant event rate before crossover

rate2

piecewise constant event rate after crossover

rate3

piecewise constant event rate for crossover

rate4

additional piecewise constant event rate for more complex crossover

rate5

additional piecewise constant event rate for more complex crossover

ratec

censoring piecewise constant event rate

tchange

a strictly increasing sequence of time points starting from zero at which event rate changes. The first element of tchange must be zero. The above rates rate1 to ratec and tchange must have the same length.

type

type of crossover, i.e. markov, semi-markov and hybrid

rp2

re-randomization prob

eps

tolerance

Details

This is to calculate the function (and its derivative)

ξ(t)=0tf~(s)SC(s)ds,\xi(t)=\int_0^t \widetilde{f}(s)S_C(s)ds,

where SCS_C is the piecewise exponential survival function of the censoring time, defined by tchange and ratec, and f~\widetilde{f} is the density for the event distribution subject to crossover defined by tchange, rate1 to rate5 and type.

Value

du

the function

duprime

its derivative

s

the survival function of f~\widetilde{f}

sc

the survival function SCS_C

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

rpwe

Examples

r1<-c(0.6,0.3)
r2<-c(0.6,0.6)
r3<-c(0.1,0.2)
r4<-c(0.5,0.4)
r5<-c(0.4,0.5)
rc<-c(0.5,0.6)
exu<-pwecxcens(t=seq(0,10,by=0.5),rate1=r1,rate2=r2,
               rate3=r3,rate4=r4,rate5=r5,ratec=rc,
               tchange=c(0,1),type=1,eps=1.0e-2)
c(exu$du,exu$duprime)

Integration of the density of piecewise exponential distribution with crossover effect, censoring and recruitment function

Description

This will calculate the functions according to the piecewise exponential distribution with crossover

Usage

pwecxpwu(t=seq(0,10,by=0.5),taur=5,
        u=c(1/taur,1/taur),ut=c(taur/2,taur),
        rate1=c(1,0.5),rate2=rate1,rate3=c(0.7,0.4),
        rate4=rate2,rate5=rate2,ratec=c(0.5,0.6),
        tchange=c(0,1),type=1,rp2=0.5,eps=1.0e-2)

Arguments

t

a vector of time points

taur

recruitment time

u

recruitment rate

ut

recruitment interval, must have the same length as u

rate1

piecewise constant event rate before crossover

rate2

piecewise constant event rate after crossover

rate3

piecewise constant event rate for crossover

rate4

additional piecewise constant event rate for more complex crossover

rate5

additional piecewise constant event rate for more complex crossover

ratec

censoring piecewise constant event rate

tchange

a strictly increasing sequence of time points starting from zero at which event rate changes. The first element of tchange must be zero. The above rates rate1 to ratec and tchange must have the same length.

type

type of crossover, i.e. markov, semi-markov and hybrid

rp2

re-randomization prob

eps

tolerance

Details

This is to calculate the function (and its derivative)

ξ(t)=0tGE(ts)f~(s)SC(s)ds,\xi(t)=\int_0^t G_E(t-s)\widetilde{f}(s)S_C(s)ds,

where GEG_E is the accrual function defined by taur, u and ut, SCS_C is the piecewise exponential survival function of the censoring time, defined by tchange and ratec, and f~\widetilde{f} is the density for the event distribution subject to crossover defined by tchange, rate1 to rate5 and type.

Value

du

the function

duprime

its derivative

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

rpwe

Examples

taur<-2
u<-c(0.6,0.4)
ut<-c(1,2)
r1<-c(0.6,0.3)
r2<-c(0.6,0.6)
r3<-c(0.1,0.2)
r4<-c(0.5,0.4)
r5<-c(0.4,0.5)
rc<-c(0.5,0.6)
exu<-pwecxpwu(t=seq(0,10,by=0.5),taur=taur,u=u,ut=ut,
        rate1=r1,rate2=r2,rate3=r3,rate4=r4,rate5=r5,ratec=rc,
        tchange=c(0,1),type=1,eps=1.0e-2)
c(exu$du,exu$duprime)

calculate the timeline when certain number of events accumulates

Description

This will calculate the timeline from study inception accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

pwecxpwufindt(target=400,ntotal=1000,taur=5,u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
                         rate11=c(1,0.5),rate21=c(0.8,0.9),rate31=c(0.7,0.4),
                         rate41=rate21,rate51=rate21,ratec1=c(0.5,0.6),
                         rate10=c(1,0.7),rate20=c(0.9,0.7),rate30=c(0.4,0.6),
                         rate40=rate20,rate50=rate20,ratec0=c(0.3,0.3),
                         tchange=c(0,1),type1=1,type0=1,
                         rp21=0.5,rp20=0.5,eps=1.0e-2,
                         init=taur,epsilon=0.000001,maxiter=100)

Arguments

target

target number of events

ntotal

total number of subjects

taur

recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob in the treatment group

rp20

re-randomization prob in the control group

eps

A small number representing the error tolerance when calculating the utility function

Φl(x)=0xslesdsxl+1\Phi_l(x)=\frac{\int_0^x s^l e^{-s}ds}{x^{l+1}}

with l=0,1,2l=0,1,2.

init

initital value of the timeline estimate

epsilon

A small number representing the error tolerance when calculating the timeline.

maxiter

Maximum number of iterations when calculating the timeline

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

t1

the calculated timeline

tvar

the true variance of the timeline estimator

eps

final tolerance

iter

Number of iterations performed

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo et al. (2018) Design and monitoring of survival trials in complex scenarios, Statistics in Medicine <doi: https://doi.org/10.1002/sim.7975>.

See Also

pwe,rpwe,qpwe,instudyfindt

Examples

target<-400
ntotal<-2000
taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(1,0.5)
r21<-c(0.5,0.8)
r31<-c(0.7,0.4)
r41<-r51<-r21
rc1<-c(0.5,0.6)
r10<-c(1,0.7)
r20<-c(0.5,1)
r30<-c(0.3,0.4)
r40<-r50<-r20
rc0<-c(0.2,0.4)
gettimeline<-pwecxpwufindt(target=target,ntotal=ntotal,
                taur=5,u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
                rate11=r11,rate21=r21,rate31=r31,rate41=r41,rate51=r51,ratec1=rc1,
                rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
                tchange=c(0,1),type1=1,type0=1,eps=1.0e-2,init=taur,epsilon=0.000001,maxiter=100)
gettimeline$t1

calculate the utility function used for varaince calculation

Description

This is a utility function to calculate the overall variance accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

pwecxpwuforvar(tfix=10,t=seq(0,10,by=0.5),taur=5,u=c(1/taur,1/taur),ut=c(taur/2,taur),
    rate1=c(1,0.5),rate2=rate1,rate3=c(0.7,0.4),rate4=rate2,rate5=rate2,ratec=c(0.5,0.6),
         tchange=c(0,1),type=1,rp2=0.5,eps=1.0e-2)

Arguments

tfix

The upper point where the integral is computed.

t

A vector of lower bounds where the integral is computed.

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

rate1

Hazard before crossover

rate2

Hazard after crossover

rate3

Hazard for time to crossover

rate4

Hazard after crossover for complex case

rate5

Hazard after crossover for complex case

ratec

Hazard for time to censoring

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate1, rate2, rate3, etc.

type

Type of crossover

rp2

re-randomization prob

eps

A small number representing the error tolerance when calculating the utility function

Φl(x)=0xslesdsxl+1\Phi_l(x)=\frac{\int_0^x s^l e^{-s}ds}{x^{l+1}}

with l=0,1,2l=0,1,2.

Details

This is to calculate the function

Bl(t,s)=0sxlGE(tx)f~(x)SC(x)dx,B_l(t,s)=\int_0^s x^l G_E(t-x)\widetilde{f}(x)S_C(x)dx,

where GEG_E is the accrual function defined by taur, u and ut, SCS_C is the piecewise exponential survival function of the censoring time, defined by tchange and ratec, and f~\widetilde{f} is the density for the event distribution subject to crossover defined by tchange, rate1 to rate5 and type. This function is useful when calculating the overall varaince and covariance.

Value

f0

the integral when l=0l=0

f1

the integral when l=1l=1

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

pwe,rpwe,qpwe,ovbeta,innervar

Examples

taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(1,0.5)
r21<-c(0.5,0.8)
r31<-c(0.7,0.4)
r41<-r51<-r21
rc1<-c(0.5,0.6)
getf<-pwecxpwuforvar(tfix=3,t=seq(0,3,by=1),taur=taur,u=u,ut=ut,
                 rate1=r11,rate2=r21,rate3=r31,rate4=r41,rate5=r51,ratec=rc1,
                 tchange=c(0,1),type=1,eps=1.0e-2)
getf

A utility function

Description

This will $int_0^t s^k lambda_1(s)S_2(s)ds$ where k=0,1,2 and rate1=lambda_1 and S_2 has hazard rate2

Usage

pwefv2(t=seq(0,5,by=0.5),rate1=c(0,5,0.8),
      rate2=rate1,tchange=c(0,3),eps=1.0e-2)

Arguments

t

A vector of time points

rate1

piecewise constant event rate

rate2

piecewise constant event rate

tchange

a strictly increasing sequence of time points starting from zero at which event rate changes. The first element of tchange must be zero. The above rates and tchange must have the same length.

eps

tolerance

Details

Let h1,h2h_1,h_2 correspond to rate1,rate2, and H1,H2H_1,H_2 be the corresponding survival functions. This function will calculate

0tskh1(s)H2(s)ds,k=0,1,2.\int_0^t s^k h_1(s)H_2(s)ds,\hspace{1cm} k=0,1,2.

Value

f0

values when k=0k=0

f1

values when k=1k=1

f2

values when k=2k=2

Note

This will provide the number of events.

Author(s)

Xiaodong Luo

References

Luo et al. (2018) Design and monitoring of survival trials in complex scenarios, Statistics in Medicine <doi: https://doi.org/10.1002/sim.7975>.

See Also

rpwe

Examples

r1<-c(0.6,0.3)
r2<-c(0.6,0.6)
tchange<-c(0,1.75)
pwefun<-pwefv2(t=seq(0,5,by=0.5),rate1=r1,rate2=r2,
              tchange=tchange,eps=1.0e-2)
pwefun

A utility functon

Description

This will calculate the more complex integration accounting for crossover

Usage

pwefvplus(t=seq(0,5,by=0.5),rate1=c(0,5,0.8),rate2=rate1,
                   rate3=c(0.1,0.2),rate4=rate2,rate5=rate2,
                   rate6=c(0.5,0.3),tchange=c(0,3),type=1,
                   rp2=0.5,eps=1.0e-2)

Arguments

t

A vector of time points

rate1

piecewise constant event rate

rate2

piecewise constant event rate

rate3

piecewise constant event rate

rate4

additional piecewise constant

rate5

additional piecewise constant

rate6

piecewise constant event rate for censoring

tchange

a strictly increasing sequence of time points starting from zero at which event rate changes. The first element of tchange must be zero. The above rates and tchange must have the same length.

type

type of the crossover, markov, semi-markov and hybrid

rp2

re-randomization prob

eps

tolerance

Details

Let h1,,h6h_1,\ldots,h_6 correspond to rate1,...,rate6, and H1,,H6H_1,\ldots,H_6 be the corresponding survival functions. Also let π2=rp2\pi_2=\code{rp2}. when type=1, we calculate

0tskh2(s)H2(s)H6(s)0sh3(u)H1(u)H3(u)/H2(u)duds;\int_0^t s^k h_2(s)H_2(s)H_6(s)\int_0^s h_3(u)H_1(u)H_3(u)/H_2(u)duds;

when type=2, we calculate

0tskH6(s)0sh3(u)H1(u)H3(u)h2(su)H2(su)duds;\int_0^t s^kH_6(s)\int_0^s h_3(u)H_1(u)H_3(u)h_2(s-u)H_2(s-u)duds;

when type=3, we calculate the sum of

π20tskH41π2(s)H6(s)0sh3(u)H1(u)H3(u)h2(su)H2π2(su)/H41π2(u)duds\pi_2\int_0^t s^kH_4^{1-\pi_2}(s)H_6(s)\int_0^s h_3(u)H_1(u)H_3(u)h_2(s-u)H_2^{\pi_2}(s-u)/H_4^{1-\pi_2}(u)duds

and

(1π2)0tskh4(s)H41π2(s)H6(s)0sh3(u)H1(u)H3(u)H2π2(su)/H41π2(u)duds;(1-\pi_2)\int_0^t s^kh_4(s)H_4^{1-\pi_2}(s)H_6(s)\int_0^s h_3(u)H_1(u)H_3(u)H_2^{\pi_2}(s-u)/H_4^{1-\pi_2}(u)duds;

when type=4, we calculate the sum of

π20tskH6(s)0sh3(u)H1(u)H3(u)h2(su)H2(su)duds\pi_2\int_0^t s^kH_6(s)\int_0^s h_3(u)H_1(u)H_3(u)h_2(s-u)H_2(s-u)duds

and

(1π2)0tskh4(s)H4(s)H6(s)0sh3(u)H1(u)H3(u)/H4(u)duds;(1-\pi_2)\int_0^t s^kh_4(s)H_4(s)H_6(s)\int_0^s h_3(u)H_1(u)H_3(u)/H_4(u)duds;

when type=5, we calculate the sum of

π20tskH6(s)0sh3(u)H1(u)H3(u)h2(su)H2(su)duds\pi_2\int_0^t s^kH_6(s)\int_0^s h_3(u)H_1(u)H_3(u)h_2(s-u)H_2(s-u)duds

and

(1π2)0tskH6(s)0sh3(u)H1(u)H3(u)h4(su)H4(su)duds.(1-\pi_2)\int_0^t s^kH_6(s)\int_0^s h_3(u)H_1(u)H_3(u)h_4(s-u)H_4(s-u)duds.

Value

f0

values when k=0k=0

f1

values when k=1k=1

f2

values when k=2k=2

Note

This provides the result of the complex integration

Author(s)

Xiaodong Luo

References

Luo et al. (2018) Design and monitoring of survival trials in complex scenarios, Statistics in Medicine <doi: https://doi.org/10.1002/sim.7975>.

See Also

rpwe

Examples

r1<-c(0.6,0.3)
r2<-c(0.6,0.6)
r3<-c(0.1,0.2)
r4<-c(0.5,0.4)
r5<-c(0.4,0.5)
r6<-c(0.4,0.5)
tchange<-c(0,1.75)
pwefun<-pwefvplus(t=seq(0,5,by=0.5),rate1=r1,rate2=r2,rate3=r3,
                 rate4=r4,rate5=r5,rate6=r6,
                 tchange=c(0,3),type=1,eps=1.0e-2)
pwefun

Calculating the powers of various the test statistics for superiority trials

Description

This will calculate the powers for the test statistics accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

pwepower(t=seq(0.1,3,by=0.5),alpha=0.05,twosided=1,taur=1.2,
             u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
             rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),
             rate41=rate21,rate51=rate21,ratec1=c(0.5,0.6),
             rate10=rate11,rate20=rate10,rate30=rate31,
             rate40=rate20,rate50=rate20,ratec0=c(0.6,0.5),
             tchange=c(0,1),type1=1,type0=1,rp21=0.5,rp20=0.5,
             eps=1.0e-2,veps=1.0e-2,epsbeta=1.0e-4,iterbeta=25,
             n=1000)

Arguments

t

a vector of time points at which power is calculated, t must be positive

alpha

type-1 error rate

twosided

twosided test or not

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob for the treatment group

rp20

re-randomization prob for the control group

eps

error tolerence

veps

error tolenrence for calculating variance

epsbeta

error tolerance for calculating overall log HR

iterbeta

maximum number of iterations for calculating overall log HR

n

total number of subjects

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

power

powers for various test statistics. Columns 2-6 are for log-rank and columns 12-16 are for cox model. Column 2 is the exact power based on log-rank/score test; column 3 uses variance approximated by Fisher information, i.e. Lakatos's method; column 4 uses approximated Fisher info by number of events i.e. 4/D(t); column 5 uses approximated Fisher info by assuming exp dist. 1/D1(t)+1/D0(t); column 6 uses Fisher information at beta. Column 12 is the exact power based on Wald test; column 13 uses variance approximated by Fisher information; column 14 uses approximated Fisher info by number of events i.e. 4/D(t); column 15 uses approximated Fisher info by assuming exp dist. 1/D1(t)+1/D0(t); column 16 uses Fisher information at beta=0.

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

pwe,rpwe,qpwe,ovbeta,innervar, pwepowerni,pwepowereq

Examples

t<-seq(3,6,by=1)
taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(0.2,0.1)
r21<-r11
r31<-c(0.03,0.02)
r41<-r51<-r21
rc1<-c(0.01,0.02)
r10<-c(0.2,0.2)
r20<-r10
r30<-c(0.02,0.01)
r40<-r50<-r20
rc0<-c(0.02,0.01)
getpower<-pwepower(t=t,alpha=0.05,twosided=1,taur=taur,u=u,ut=ut,pi1=0.5,
                   rate11=r11,rate21=r21,rate31=r31,rate41=r41,rate51=r51,ratec1=rc1,
                   rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
                   tchange=c(0,1),type1=1,type0=1,n=1000)
###powers at each time point
cbind(t,getpower$power[,c(2:4,12:14)])

Calculating the powers of various the test statistics for equivalence trials

Description

This will calculate the powers for the test statistics accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

pwepowereq(t=seq(0.1,3,by=0.5),uppermargin=1.3,lowermargin=1/uppermargin,
           alpha=0.05,taur=1.2,u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
             rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),
             rate41=rate21,rate51=rate21,ratec1=c(0.5,0.6),
             rate10=rate11,rate20=rate10,rate30=rate31,
             rate40=rate20,rate50=rate20,ratec0=c(0.6,0.5),
             tchange=c(0,1),type1=1,type0=1,
             rp21=0.5,rp20=0.5,eps=1.0e-2,veps=1.0e-2,
             epsbeta=1.0e-4,iterbeta=25,n=1000)

Arguments

t

a vector of time points at which power is calculated, t must be positive

uppermargin

the upper margin for the hazard ratio

lowermargin

the lower margin for the hazard ratio

alpha

type-1 error rate

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob in the treatment group

rp20

re-randomization prob in the control group

eps

error tolerence

veps

error tolenrence for calculating variance

epsbeta

error tolerance for calculating overall log HR

iterbeta

maximum number of iterations for calculating overall log HR

n

total number of subjects

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

power

powers for cox model. First column is the more accurate power, second column is the power assuming the Fisher information equal to the varaince of beta

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

pwe,rpwe,qpwe,ovbeta,innervar, pwepower,pwepowerni

Examples

t<-seq(3,6,by=1)
taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(0.2,0.1)
r21<-r11
r31<-c(0.03,0.02)
r41<-r51<-r21
rc1<-c(0.01,0.02)
r10<-c(0.2,0.2)
r20<-r10
r30<-c(0.02,0.01)
r40<-r50<-r20
rc0<-c(0.02,0.01)
getpowereq<-pwepowereq(t=t,uppermargin=1.3,lowermargin=0.8,alpha=0.05,taur=taur,
            u=u,ut=ut,pi1=0.5,rate11=r11,rate21=r21,rate31=r31,
            rate41=r41,rate51=r51,ratec1=rc1,
            rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
            tchange=c(0,1),type1=1,type0=1,n=1000)
###powers at each time point
cbind(t,getpowereq$power[,1:3])

Calculating the timepoint where a certain power of the specified test statistics is obtained

Description

This will calculate the timepoint where a certain power of the specified test statistics is obtained accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

pwepowerfindt(power=0.9,alpha=0.05,twosided=1,tupp=5,tlow=1,taur=1.2,
                     u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
                     rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),
                     rate41=rate21,rate51=rate21,ratec1=c(0.5,0.6),
                     rate10=rate11,rate20=rate10,rate30=rate31,
                     rate40=rate20,rate50=rate20,ratec0=c(0.6,0.5),
                     tchange=c(0,1),type1=1,type0=1,
                     rp21=0.5,rp20=0.5,eps=1.0e-2,veps=1.0e-2,
                     epsbeta=1.0e-04,iterbeta=25,
                     n=1000,testtype=1,maxiter=20,itereps=0.001)

Arguments

power

the desired power

alpha

type-1 error

twosided

twoside test or not

tupp

an upper time point where the power should be larger than power

tlow

a lower time point where the power should be smaller than power

taur

recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob in the treatment group

rp20

re-randomization prob in the control group

eps

error tolerence

veps

error tolenrence for calculating variance

epsbeta

error tolerance for calculating overall log HR

iterbeta

maximum number of iterations for calculating overall log HR

n

total number of subjects

testtype

test statistics, =1 log-rank;=2 Cox model; =3 log-rank with robust variance

maxiter

maximum number of bi-section iterations

itereps

error tolerance of power

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

testtype

type of statistic, =1 log-rank;=2 Cox model; =3 log-rank with robust variance

time

time calculated when the iterations stop

power

the power at time

err

distance from the desired power

k

number of bi-section iterations performed

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

pwe,rpwe,qpwe,ovbeta,innervar

Examples

t<-seq(3,6,by=1)
taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(0.2,0.1)
r21<-r11
r31<-c(0.03,0.02)
r41<-r51<-r21
rc1<-c(0.01,0.02)
r10<-c(0.2,0.2)
r20<-r10
r30<-c(0.02,0.01)
r40<-r50<-r20
rc0<-c(0.02,0.01)
getpower<-pwepower(t=t,alpha=0.05,twosided=1,taur=taur,u=u,ut=ut,pi1=0.5,
                   rate11=r11,rate21=r21,rate31=r31,rate41=r41,rate51=r51,ratec1=rc1,
                   rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
                   tchange=c(0,1),type1=1,type0=1,n=1000)
###powers at each time point
cbind(t,getpower$power[,1:3])

###90% power should be in (3,3.5)
getpwtime<-pwepowerfindt(power=0.9,alpha=0.05,twosided=1,tupp=3.5,tlow=3,taur=taur,
        u=u,ut=ut,pi1=0.5,rate11=r11,rate21=r21,rate31=r31,rate41=r41,rate51=r51,ratec1=rc1,
        rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
        tchange=c(0,1),type1=1,type0=1,n=1000,testtype=1,maxiter=30)
getpwtime

Calculating the powers of various the test statistics for non-inferiority trials

Description

This will calculate the powers for the test statistics accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

pwepowerni(t=seq(0.1,3,by=0.5),nimargin=1.3,alpha=0.05,twosided=0,taur=1.2,
           u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
           rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),
           rate41=rate21,rate51=rate21,ratec1=c(0.5,0.6),
           rate10=rate11,rate20=rate10,rate30=rate31,
           rate40=rate20,rate50=rate20,ratec0=c(0.6,0.5),
           tchange=c(0,1),type1=1,type0=1,
           rp21=0.5,rp20=0.5,eps=1.0e-2,veps=1.0e-2,
           epsbeta=1.0e-4,iterbeta=25,n=1000)

Arguments

t

a vector of time points at which power is calculated, t must be positive

nimargin

the non-inferiority margin for the hazard ratio

alpha

type-1 error rate

twosided

twosided test or not

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob in the treatment group

rp20

re-randomization prob in the control group

eps

error tolerence

veps

error tolenrence for calculating variance

epsbeta

error tolerance for calculating overall log HR

iterbeta

maximum number of iterations for calculating overall log HR

n

total number of subjects

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

power

powers for cox model. First column is the more accurate power, second column is the power assuming the Fisher information equal to the varaince of beta

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

pwe,rpwe,qpwe,ovbeta,innervar, pwepower,pwepowereq

Examples

t<-seq(3,6,by=1)
taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(0.2,0.1)
r21<-r11
r31<-c(0.03,0.02)
r41<-r51<-r21
rc1<-c(0.01,0.02)
r10<-c(0.2,0.2)
r20<-r10
r30<-c(0.02,0.01)
r40<-r50<-r20
rc0<-c(0.02,0.01)
getpowerni<-pwepowerni(t=t,nimargin=1.3,alpha=0.05,twosided=1,taur=taur,u=u,ut=ut,pi1=0.5,
                   rate11=r11,rate21=r21,rate31=r31,rate41=r41,rate51=r51,ratec1=rc1,
                   rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
                   tchange=c(0,1),type1=1,type0=1,n=1000)
###powers at each time point
cbind(t,getpowerni$power[,1:3])

simulating the test statistics

Description

This will simulate the test statistics accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

pwesim(t=seq(1,2,by=0.1),taur=1.2,u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
                     rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),
                     rate41=rate21,rate51=rate21,ratec1=c(0.5,0.6),
                     rate10=rate11,rate20=rate10,rate30=rate31,
                     rate40=rate20,rate50=rate20,ratec0=c(0.6,0.5),
                     tchange=c(0,1),type1=1,type0=1,
                     rp21=0.5,rp20=0.5,
                     n=1000,rn=200,testtype=c(1,2,3,4))

Arguments

t

a vector of time points

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob in the treatment group

rp20

re-randomization prob in the control group

n

number of subjects

rn

number of simulations

testtype

types of test statistics.

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

outr

test statistics at each time point and each simulation run

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

pwe,rpwe,qpwe,ovbeta,innervar

Examples

taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(1,0.5)
r21<-c(0.5,0.8)
r31<-c(0.7,0.4)
r41<-r51<-r21
rc1<-c(0.5,0.6)
r10<-c(1,0.7)
r20<-c(0.5,1)
r30<-c(0.3,0.4)
r40<-r50<-r20
rc0<-c(0.2,0.4)
ar<-pwesim(t=seq(1,2,by=0.1),taur=taur,u=u,ut=ut,pi1=0.5,
        rate11=r11,rate21=r21,rate31=r31,rate41=r41,rate51=r51,ratec1=rc1,
        rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
        tchange=c(0,1),type1=1,type0=1,
        n=300,rn=10)

Piecewise uniform distribution: distribution

Description

This will calculate the distribution function of the piecewise uniform distribution

Usage

pwu(t=seq(0,1,by=0.1),u=c(0,5,0.5),ut=c(1,2))

Arguments

t

a vector of time points

u

piecewise constant density

ut

a strictly increasing sequence of time points defining the pieces. The first element must be strictly greater than zero. u and ut must have the same length.

Details

Let f(t)=j=1mujI(tj1<ttj)f(t)=\sum_{j=1}^m u_j I(t_{j-1}<t\le t_j) be the density function, where u1,,umu_1,\ldots,u_m are the corresponding elements of u and t1,,tmt_1,\ldots,t_{m} are the corresponding elements of ut and t0=0t_0=0. The distribution function

F(t)=j=1muj(ttjttj1).F(t)=\sum_{j=1}^m u_j(t\wedge t_j-t\wedge t_{j-1}).

User must make sure that j=1muj(tjtj1)=1\sum_{j=1}^m u_j (t_j-t_{j-1})=1 before using this function.

Value

dist

distribution

Note

This provides distribution of the piecewise uniform distribution

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

pwe

Examples

t<-seq(-1,3,by=0.5)
u<-c(0.6,0.4)
ut<-c(1,2)
pwud<-pwu(t=t,u=u,ut=ut)
pwud

Piecewise exponential distribution: quantile function

Description

This will provide the quantile function of the specified piecewise exponential distribution

Usage

qpwe(p=seq(0,1,by=0.1),rate=c(0,5,0.8),tchange=c(0,3))

Arguments

p

a vector of probabilities

rate

piecewise constant event rate

tchange

time points at which event rate changes. This must be an strictly increasing sequence starting from zero. rate and tchange must have the same length.

Details

More details

Value

q

quantiles

Note

This provides the quantile function related to the piecewise exponetial distribution

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

piecewise exponential

Examples

p<-seq(0,1,by=0.1)
rate<-c(0.6,0.3)
tchange<-c(0,1.75)
pweq<-qpwe(p=p,rate=rate,tchange=tchange)
pweq

Piecewise uniform distribution: quantile function

Description

This will provide the quantile function of the specified piecewise uniform distribution

Usage

qpwu(p=seq(0,1,by=0.1),u=c(0,5,0.5),ut=c(1,2))

Arguments

p

a vector of probabilities

u

piecewise constant density

ut

time points at which event rate changes. This must be an strictly increasing sequence. ut and u must have the same length.

Details

Let f(t)=j=1mujI(tj1<ttj)f(t)=\sum_{j=1}^m u_j I(t_{j-1}<t\le t_j) be the density function, where u1,,umu_1,\ldots,u_m are the corresponding elements of u and t1,,tmt_1,\ldots,t_{m} are the corresponding elements of ut and t0=0t_0=0. The distribution function

F(t)=j=1muj(ttjttj1).F(t)=\sum_{j=1}^m u_j(t\wedge t_j-t\wedge t_{j-1}).

User must make sure that j=1muj(tjtj1)=1\sum_{j=1}^m u_j (t_j-t_{j-1})=1 before using this function.

Value

q

quantiles

Note

This provides the quantile function related to the piecewise uniform distribution

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

piecewise uniform

Examples

p<-seq(0,1,by=0.1)
u<-c(0.6,0.4)
ut<-c(1,2)
pwuq<-qpwu(p=p,u=u,ut=ut)
pwuq

Calculation of the variance and covariance of estimated restricted mean survival time

Description

A function to calculate the variance and covariance of estimated restricted mean survival time using data from different cut-off points accounting for delayed treatment, discontinued treatment and non-uniform entry

Usage

rmstcov(t1cut=2.0,t1study=2.5,t2cut=3.0,t2study=3.5,taur=5,
        u=c(1/taur,1/taur),ut=c(taur/2,taur),
        rate1=c(1,0.5),rate2=rate1,rate3=c(0.7,0.4),
        rate4=rate2,rate5=rate2,ratec=c(0.5,0.6),
        tchange=c(0,1),type=1,rp2=0.5,
        eps=1.0e-2,veps=1.0e-2)

Arguments

t1cut

time point at which rmst is calculated

t1study

the study time point from first patient in, it must be larger than t1cut. This will be used for study monitoring.

t2cut

time point at which rmst is calculated. t2cut must be not smaller than t1cut.

t2study

the study time point from first patient in, it must be larger than t2cut. This will be used for study monitoring.

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

rate1

piecewise constant event rate before crossover

rate2

piecewise constant event rate after crossover

rate3

piecewise constant event rate for crossover

rate4

additional piecewise constant event rate for more complex crossover

rate5

additional piecewise constant event rate for more complex crossover

ratec

Hazard for time to censoring

tchange

a strictly increasing sequence of time points starting from zero at which event rate changes. The first element of tchange must be zero. The above rates rate1 to ratec and tchange must have the same length.

type

type of crossover, 1=markov, 2=semi-markov, 3=hybrid

rp2

re-randomization probability to receive the rescue treatment when semi-markov crossover occurs. When it happens, the overall hazard will be pi2*r2(t-s)+(1-pi2)*r4(t), where r2 is the hazard for the semi-markov rescue treatment and r4 is hazard for the markov rescue treatment.

eps

A small number representing the error tolerance when calculating the utility function

Φl(x)=0xslesdsxl+1\Phi_l(x)=\frac{\int_0^x s^l e^{-s}ds}{x^{l+1}}

with l=0,1,2l=0,1,2.

veps

A small number representing the error tolerance when calculating the variance.

Details

More details

Value

t1cut

time point at which rmst is calculated

t1study

the study time point from first patient in, it must be larger than t1cut. This will be used for study monitoring.

t2cut

time point at which rmst is calculated. t2cut must be not smaller than t1cut.

t2study

the study time point from first patient in, it must be larger than t2cut. This will be used for study monitoring.

rmst

rmst at cut-point t1cut with study time t1study

rmst1

rmst at cut-point t2cut with study time t2study

rmstx

rmst at cut-point t1cut with study time t2study, which should be the same as rmst.

v

the variance of rmst

v1

the variance of rmst1

cov

the covariance of rmst and rmst1

cov1

another covariance of rmst and rmst1, should be the same as cov

Note

This calculates the "true" variance and covariance of restricted mean survival times

Author(s)

Xiaodong Luo

References

Luo et al. (2018) Design and monitoring of survival trials in complex scenarios, Statistics in Medicine <doi: https://doi.org/10.1002/sim.7975>.

Examples

r1<-c(0.6,0.3)
r2<-c(0.6,0.6)
r3<-c(0.1,0.2)
r4<-c(0.5,0.4)
r5<-c(0.4,0.5)
rc<-c(0.1,0.1)
rmcov<-rmstcov(t1cut=2.0,t1study=2.5,t2cut=3.0,t2study=3.5,taur=5,
        rate1=r1,rate2=r2,rate3=r3,rate4=r4,rate5=r5,ratec=rc,
        tchange=c(0,1),type=1)
rmcov

Estimate the restricted mean survival time (RMST) and its variance from data

Description

A function to estimate the restricted mean survival time (RMST) and its variance from data

Usage

rmsth(y=c(1,2,3),d=c(1,1,0),tcut=2.0,eps=1.0e-08)

Arguments

y

observed times

d

non-censoring indicators

tcut

time point at which rmst is calculated

eps

A small number representing the error tolerance when comparing the event times

Details

More details

Value

tcut

time point at which rmst is calculated

rmst

estimated RMST

var

estimated variance of rmst

vadd

estimated variance-covariance term of rmst

Note

This estimates the restricted mean survival time and its asymptotic variance

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

Examples

lamt<-0.8
lamc<-0.4
n<-3000
tcut<-2.0
truermst<-(1-exp(-lamt*tcut))/lamt
tt<-rexp(n)/lamt
cc<-rexp(n)/lamc
yy<-pmin(tt,cc)
dd<-rep(1,n)
dd[tt>cc]<-0
aest<-rmsth(y=yy,d=dd,tcut=tcut)
aest

Calculate powers at different cut-points based on difference of restricted mean survival times (RMST)

Description

A function to calculate powers at different cut-points based on difference of restricted mean survival times (RMST) account for delayed treatment, discontinued treatment and non-uniform entry

Usage

rmstpower(tcut=2,tstudy=seq(tcut,tcut+2,by=0.5),alpha=0.05,twosided=1,
          taur=1.2,u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
          rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),
          rate41=rate21,rate51=rate21,ratec1=c(0.5,0.6),
          rate10=rate11,rate20=rate10,rate30=rate31,
          rate40=rate20,rate50=rate20,ratec0=c(0.6,0.5),
          tchange=c(0,1),type1=1,type0=1,rp21=0.5,rp20=0.5,
          eps=1.0e-2,veps=1.0e-2,n=1000)

Arguments

tcut

timepoint at which rmst is calculated

tstudy

a vector of study time points, which must be not smaller than tcut

alpha

type-1 error rate

twosided

twosided test=1 or not

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob for the treatment group

rp20

re-randomization prob for the control group

eps

error tolerence

veps

error tolenrence for calculating variance

n

total number of subjects, both groups combined

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

power

power

rmst1

rmst in the treatment group

se1

standard error of the rmst in the treatment group

rmst0

rmst in the control group

se0

standard error of the rmst in the control group

drmst

rmst1-rmst0

sed

standard error of the mean difference

Note

This calculates the restricted mean survival times between the treatment and control groups and their standard errors

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

Examples

tcut<-3.0
tstudy<-seq(3,6,by=1)
taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(0.2,0.1)
r21<-r11
r31<-c(0.03,0.02)
r41<-r51<-r21
rc1<-c(0.01,0.02)
r10<-c(0.2,0.2)
r20<-r10
r30<-c(0.02,0.01)
r40<-r50<-r20
rc0<-c(0.02,0.01)
getrmst<-rmstpower(tcut=tcut,tstudy=tstudy,alpha=0.05,twosided=1,
          taur=taur,u=u,ut=ut,pi1=0.5,
          rate11=r11,rate21=r21,rate31=r31,rate41=r41,rate51=r51,ratec1=rc1,
          rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
          tchange=c(0,1),type1=1,type0=1,rp21=0.5,rp20=0.5,n=1000)
###powers at each time point
cbind(tstudy,getrmst$power)

Calculating the timepoint where a certain power of mean difference of RMSTs is obtained

Description

This will calculate the timepoint where a certain power of the mean difference of RMSTs is obtained accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

rmstpowerfindt(power=0.9,alpha=0.05,twosided=1,tcut=2,tupp=5,tlow=3.0,taur=1.2,
           u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
           rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),
           rate41=rate21,rate51=rate21,ratec1=c(0.5,0.6),
           rate10=rate11,rate20=rate10,rate30=rate31,
           rate40=rate20,rate50=rate20,ratec0=c(0.6,0.5),
           tchange=c(0,1),type1=1,type0=1,
           rp21=0.5,rp20=0.5,eps=1.0e-2,veps=1.0e-2,
           n=1000,maxiter=20,itereps=0.001)

Arguments

power

the desired power

alpha

type-1 error

twosided

twoside test or not

tcut

time point at which rmst is calculated

tupp

an upper study time point where the power should be larger than power

tlow

a lower study time point where the power should be smaller than power, tlow must be not smaller than tcut

taur

recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob in the treatment group

rp20

re-randomization prob in the control group

eps

error tolerence

veps

error tolenrence for calculating variance

n

total number of subjects

maxiter

maximum number of bi-section iterations

itereps

error tolerance of power

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

time

time calculated when the iterations stop

power

the power at time

err

distance from the desired power

k

number of bi-section iterations performed

Note

Version 1.0 (8/8/2017)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

pwe,rpwe,qpwe,ovbeta,innervar

Examples

tcut<-3.0
tstudy<-seq(3,6,by=0.2)
taur<-2
u<-c(0.3,0.7)
ut<-c(taur/2,taur)
r11<-c(0.2,0.1)
r21<-r11
r31<-c(0.03,0.02)
r41<-r51<-r21
rc1<-c(0.05,0.04)
r10<-c(0.22,0.22)
r20<-r10
r30<-c(0.02,0.01)
r40<-r50<-r20
rc0<-c(0.04,0.05)
ntotal<-1200
getrmst<-rmstpower(tcut=tcut,tstudy=tstudy,alpha=0.05,twosided=1,
        taur=taur,u=u,ut=ut,pi1=0.5,
        rate11=r11,rate21=r21,rate31=r31,rate41=r41,rate51=r51,ratec1=rc1,
        rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
        tchange=c(0,1),type1=1,type0=1,rp21=0.5,rp20=0.5,n=ntotal)
###powers at each time point
cbind(tstudy,getrmst$power)

###90 percent power should be in (3,4)
gettime<-rmstpowerfindt(power=0.9,alpha=0.05,twosided=1,tcut=tcut,tupp=4,tlow=3.0,taur=taur,
          u=u,ut=ut,pi1=0.5,rate11=r11,rate21=r21,rate31=r31,rate41=r41,rate51=r51,ratec1=rc1,
          rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
          tchange=c(0,1),type1=1,type0=1,rp21=0.5,rp20=0.5,eps=1.0e-2,veps=1.0e-2,
          n=ntotal,maxiter=20,itereps=0.0001)
gettime

simulating the restricted mean survival times

Description

This will simulate the test statistics accouting for staggered entry, delayed treatment effect, treatment crossover and loss to follow-up.

Usage

rmstsim(tcut=c(1,2),tstudy=tcut+0.2,taur=1.2,
        u=c(1/taur,1/taur),ut=c(taur/2,taur),pi1=0.5,
        rate11=c(1,0.5),rate21=rate11,rate31=c(0.7,0.4),
        rate41=rate21,rate51=rate21,ratec1=c(0.5,0.6),
        rate10=rate11,rate20=rate10,rate30=rate31,
        rate40=rate20,rate50=rate20,ratec0=c(0.6,0.5),
        tchange=c(0,1),type1=1,type0=1,rp21=0.5,rp20=0.5,
        n=1000,rn=200,eps=1.0E-08)

Arguments

tcut

a vector of time points at which rmst are calculated

tstudy

a vector of study time points, should be the same length as tcut and should be not less than tcut element-wise

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

pi1

Allocation probability for the treatment group

rate11

Hazard before crossover for the treatment group

rate21

Hazard after crossover for the treatment group

rate31

Hazard for time to crossover for the treatment group

rate41

Hazard after crossover for the treatment group for complex case

rate51

Hazard after crossover for the treatment group for complex case

ratec1

Hazard for time to censoring for the treatment group

rate10

Hazard before crossover for the control group

rate20

Hazard after crossover for the control group

rate30

Hazard for time to crossover for the control group

rate40

Hazard after crossover for the control group for complex case

rate50

Hazard after crossover for the control group for complex case

ratec0

Hazard for time to censoring for the control group

tchange

A strictly increasing sequence of time points at which the event rates changes. The first element of tchange must be zero. It must have the same length as rate11, rate21, rate31, etc.

type1

Type of crossover in the treatment group

type0

Type of crossover in the control group

rp21

re-randomization prob in the treatment group

rp20

re-randomization prob in the control group

n

number of subjects

rn

number of simulations

eps

tolerence for comparing event times

Details

The hazard functions corresponding to rate11,...,rate51,ratec1, rate10,...,rate50,ratec0 are all piecewise constant function taking the form λ(t)=j=1mλjI(tj1t<tj)\lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where λ1,,λm\lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t0,,tm1t_0,\ldots,t_{m-1} are the corresponding elements of tchange, tm=t_m=\infty. Note that all the rates must have the same tchange.

Value

outr

test statistics at each pair of tcut and tstudy in column and each simulation run in row

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo et al. (2018) Design and monitoring of survival trials in complex scenarios, Statistics in Medicine <doi: https://doi.org/10.1002/sim.7975>.

See Also

pwe,rpwe,qpwe,ovbeta

Examples

tcuta<-c(2,3)
taur<-1.2
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(1,0.5)
r21<-c(0.5,0.8)
r31<-c(0.7,0.4)
r41<-r51<-r21
rc1<-c(0.5,0.6)
r10<-c(1.5,0.7)
r20<-c(0.5,1)
r30<-c(0.3,0.4)
r40<-r50<-r20
rc0<-c(0.2,0.4)
ar<-rmstsim(tcut=tcuta,tstudy=tcuta+0.1,taur=taur,u=u,ut=ut,pi1=0.5,
            rate11=r11,rate21=r21,rate31=r31,rate41=r41,rate51=r51,ratec1=rc1,
            rate10=r10,rate20=r20,rate30=r30,rate40=r40,rate50=r50,ratec0=rc0,
            tchange=c(0,1),type1=1,type0=1,
            n=300,rn=200)
##Empirical power
apply(ar$outr>1.96,2,mean)

A utility function to calculate the true restricted mean survival time (RMST) and its variance account for delayed treatment, discontinued treatment and non-uniform entry

Description

A utility function to calculate the true restricted mean survival time (RMST) and its variance account for delayed treatment, discontinued treatment and non-uniform entry

Usage

rmstutil(tcut=2.0,tstudy=5.0,taur=5,u=c(1/taur,1/taur),ut=c(taur/2,taur),
        rate1=c(1,0.5),rate2=rate1,rate3=c(0.7,0.4),
        rate4=rate2,rate5=rate2,ratec=c(0.5,0.6),
        tchange=c(0,1),type=1,rp2=0.5,
        eps=1.0e-2,veps=1.0e-2)

Arguments

tcut

time point at which rmst is calculated

tstudy

the study time point from first patient in, it must be not smaller than tcut.

taur

Recruitment time

u

Piecewise constant recuitment rate

ut

Recruitment intervals

rate1

piecewise constant event rate before crossover

rate2

piecewise constant event rate after crossover

rate3

piecewise constant event rate for crossover

rate4

additional piecewise constant event rate for more complex crossover

rate5

additional piecewise constant event rate for more complex crossover

ratec

Hazard for time to censoring

tchange

a strictly increasing sequence of time points starting from zero at which event rate changes. The first element of tchange must be zero. The above rates rate1 to ratec and tchange must have the same length.

type

type of crossover, 1=markov, 2=semi-markov, 3=hybrid

rp2

re-randomization probability to receive the rescue treatment when semi-markov crossover occurs. When it happens, the overall hazard will be rp2*r2(t-s)+(1-rp2)*r4(t), where r2 is the hazard for the semi-markov rescue treatment and r4 is hazard for the markov rescue treatment.

eps

A small number representing the error tolerance when calculating the utility function

Φl(x)=0xslesdsxl+1\Phi_l(x)=\frac{\int_0^x s^l e^{-s}ds}{x^{l+1}}

with l=0,1,2l=0,1,2.

veps

A small number representing the error tolerance when calculating the variance.

Details

More details

Value

tcut

time point at which rmst is calculated

tstudy

the study time point from first patient in, it must be not smaller than tcut

rmst

rmst at cut-point tcut

var

the variance of rmst

vadd

the additional variance term of rmst

Note

This calculates the "true" variance of restricted mean survival times

Author(s)

Xiaodong Luo

References

Luo et al. (2018) Design and monitoring of survival trials in complex scenarios, Statistics in Medicine <doi: https://doi.org/10.1002/sim.7975>.

Examples

r1<-c(0.6,0.3)
r2<-c(0.6,0.6)
r3<-c(0.1,0.2)
r4<-c(0.5,0.4)
r5<-c(0.4,0.5)
rc<-c(0.1,0.1)
rmt<-rmstutil(tcut=2.0,tstudy=5.0,taur=5,
        rate1=r1,rate2=r2,rate3=r3,
        rate4=r4,rate5=r5,ratec=rc,
        tchange=c(0,1),type=1,rp2=0.5,
        eps=1.0e-2,veps=1.0e-2)
rmt

Piecewise exponential distribution: random number generation

Description

This will generate random numbers according to the specified piecewise exponential distribution

Usage

rpwe(nr=10,rate=c(0,5,0.8),tchange=c(0,3))

Arguments

nr

number of random numbers to be generated

rate

piecewise constant event rate

tchange

a strictly increasing sequence of time points starting from zero at which event rate changes. The first element of tchange must be zero. rate and tchange must have the same length.

Details

More details

Value

r

random numbers

Note

This provides a random number generator of the piecewise exponetial distribution

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

piecewise exponential

Examples

nr<-10
rate<-c(0.6,0.3)
tchange<-c(0,1.75)
pwer<-rpwe(nr=nr,rate=rate,tchange=tchange)
pwer

Piecewise exponential distribution with crossover effect: random number generation

Description

This will generate random numbers according to the piecewise exponential distribution with crossover

Usage

rpwecx(nr=1,rate1=c(1,0.5),rate2=rate1,rate3=c(0.7,0.4),
rate4=rate2,rate5=rate2,tchange=c(0,1),type=1,rp2=0.5)

Arguments

nr

number of random numbers to be generated

rate1

piecewise constant event rate before crossover

rate2

piecewise constant event rate after crossover

rate3

piecewise constant event rate for crossover

rate4

additional piecewise constant event rate for more complex crossover

rate5

additional piecewise constant event rate for more complex crossover

tchange

a strictly increasing sequence of time points starting from zero at which event rate changes. The first element of tchange must be zero. The above rates rate1 to rate6 and tchange must have the same length.

type

type of crossover, 1=markov, 2=semi-markov, 3=hybrid

rp2

re-randomization probability to receive the rescue treatment when semi-markov crossover occurs. When it happens, the overall hazard will be pi2*r2(t-s)+(1-pi2)*r4(t), where r2 is the hazard for the semi-markov rescue treatment and r4 is hazard for the markov rescue treatment.

Details

More details

Value

r

random numbers for the event time

rx

random numbers for the crossover time

cxind

indicators for the crossover, the first column indicates whether crossover occurs, i.e. rx<r\code{rx}<\code{r}. When type=3,4,5, the second column of cxind indicates whether it crosses to the arm with rate2

Note

This provides a random number generator of the piecewise exponetial distribution with crossover

Author(s)

Xiaodong Luo

References

Luo et al. (2018) Design and monitoring of survival trials in complex scenarios, Statistics in Medicine <doi: https://doi.org/10.1002/sim.7975>.

See Also

rpwe

Examples

r1<-c(0.6,0.3)
r2<-c(0.6,0.6)
r3<-c(0.1,0.2)
r4<-c(0.5,0.4)
r5<-c(0.4,0.5)
pwecxr<-rpwecx(nr=10,rate1=r1,rate2=r2,rate3=r3,rate4=r4,rate5=r5,tchange=c(0,1),type=1)
pwecxr$r

Piecewise uniform distribution: random number generation

Description

This will generate random numbers according to the specified piecewise uniform distribution

Usage

rpwu(nr=10,u=c(0,6,0.4),ut=c(1,2))

Arguments

nr

number of random numbers to be generated

u

piecewise constant density

ut

a strictly increasing sequence of time points defining the pieces. The first element must be strictly greater than zero. u and ut must have the same length.

Details

Let f(t)=j=1mujI(tj1<ttj)f(t)=\sum_{j=1}^m u_j I(t_{j-1}<t\le t_j) be the density function, where u1,,umu_1,\ldots,u_m are the corresponding elements of u and t1,,tmt_1,\ldots,t_{m} are the corresponding elements of ut and t0=0t_0=0. The distribution function

F(t)=j=1muj(ttjttj1).F(t)=\sum_{j=1}^m u_j(t\wedge t_j-t\wedge t_{j-1}).

User must make sure that j=1muj(tjtj1)=1\sum_{j=1}^m u_j (t_j-t_{j-1})=1 before using this function.

Value

r

random numbers

Note

This provides a random number generator of the piecewise uniform distribution

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

See Also

rpwe

Examples

nr<-10
u<-c(0.6,0.4)
ut<-c(1,2)
pwur<-rpwu(nr=nr,u=u,ut=ut)
pwur

A utility function

Description

A utility function to calculate a ratio.

Usage

spf(x=seq(-1,1,by=0.2),eps=1.0e-3)

Arguments

x

A vector

eps

tolerance

Details

This is to calculate

Φl(x)=0xslesdsxl+1,l=0,1,2.\Phi_l(x)=\frac{\int_0^x s^le^{-s}ds}{x^{l+1}},\hspace{0.5cm}l=0,1,2.

This function is well defined even when x=0. However, it is numerical chanllenging to calculate it when x is small. So when xeps|x|\le \code{eps} we approximate this function and the absolute error is eps5\code{eps}^5.

Value

fx1

when l=0l=0;

fx2

when l=1l=1;

fx3

when l=2l=2.

Note

Version 1.0 (7/19/2016)

Author(s)

Xiaodong Luo

References

Luo, et al. (2017)

Examples

fun<-spf(x=seq(-1,1,by=0.2),eps=1.0e-3)
fun

A utility function to calculate the weighted log-rank statistics and their varainces given the weights

Description

A utility function to calculate the weighted log-rank statistics and their varainces given the weights

Usage

wlrcal(n=10,te=c(1,2,3),tfix=2.0,dd1=c(1,0,1),dd0=c(0,1,0),r1=c(1,2,3),r0=c(1,2,3),
       weights=matrix(1,nrow=length(te),ncol=1),eps=1.0e-08)

Arguments

n

total number of subjects in the study

te

(ascendingly) ordered unique event times from both groups

tfix

time point where weighted log-rank is calcualted

dd1

number of events from treatment group at each te

dd0

number of events from control group at each te

r1

number of at-risk subjects from treatment group at each te

r0

number of at-risk subjects from control group at each te

weights

user specified weights, each column is a set of weights at each te

eps

tolerence when comparing event times

Details

More details

Value

test

unscaled test statistics

var

variances of the unsclaed test statistics

wlr

weighted log-rank statistics, i.e. scaled test statsitics

wlcor

the correlation matrix of the weighted log-rank statistics

Author(s)

Xiaodong Luo

Examples

lr<-wlrcal(n=10,te=c(1,2,3),tfix=2.0,dd1=c(1,0,1),dd0=c(0,1,0),r1=c(1,2,3),r0=c(1,2,3))
lr

A function to calculate the various weighted log-rank statistics and their varainces

Description

A function to calculate the weighted log-rank statistics and their varainces given the weights including log-rank, gehan, Tarone-Ware, Peto-Peto, mPeto-Peto and Fleming-Harrington

Usage

wlrcom(y,d,z,tfix=max(y),p=c(1),q=c(1),eps=1.0e-08)

Arguments

y

observed times

d

non-censoring indicators

z

group indicators, z=1: treatment, z=0 control

tfix

time point at which weighted log-rank is calculated

p

a vector of power numbers for S in the Fleming-Harrington weight

q

a vector of power numbers for 1-S in the Fleming-Harrington weight, q and p should have the same length

eps

the error tolerance when comparing event times

Details

V1:3/21/2018

Value

n

total number of subjects, combined groups

test

unscaled test statistics

var

variances of the unsclaed test statistics

wlr

weighted log-rank statistics, i.e. scaled test statsitics

pvalue

two-sided p-values of wlr

Author(s)

Xiaodong Luo

Examples

n<-1000
pi1<-0.5
taur<-2.8
u<-c(1/taur,1/taur)
ut<-c(taur/2,taur)
r11<-c(1,0.5)
r21<-c(0.5,0.8)
r31<-c(0.7,0.4)
r41<-r51<-r21
rc1<-c(0.5,0.6)
r10<-c(1,0.7)
r20<-c(0.5,1)
r30<-c(0.3,0.4)
r40<-r50<-r20
rc0<-c(0.2,0.4)
tchange<-c(0,1.873)
tcut<-2

E<-T<-C<-z<-delta<-rep(0,n)
E<-rpwu(nr=n,u=u,ut=ut)$r
z<-rbinom(n,1,pi1)
n1<-sum(z)
n0<-sum(1-z)
C[z==1]<-rpwe(nr=n1,rate=rc1,tchange=tchange)$r
C[z==0]<-rpwe(nr=n0,rate=rc0,tchange=tchange)$r
T[z==1]<-rpwecx(nr=n1,rate1=r11,rate2=r21,rate3=r31,
                rate4=r41,rate5=r51,tchange=tchange,type=1)$r
T[z==0]<-rpwecx(nr=n0,rate1=r10,rate2=r20,rate3=r30,
                rate4=r40,rate5=r50,tchange=tchange,type=1)$r
y<-pmin(pmin(T,C),tcut-E)
y1<-pmin(C,tcut-E)
d<-rep(0,n);
d[T<=y]<-1

wlr4<-wlrcom(y=y,d=d,z=z,p=c(1,1),q=c(0,1))
wlr4

A utility function to calculate some common functions in contructing weights

Description

A utility function to calculate some common functions in contructing weights

Usage

wlrutil(y=c(1,2,3),d=c(1,0,1),z=c(1,0,0),te=c(1,3),eps=1.0e-08)

Arguments

y

observed times

d

non-censoring indicators

z

group indicators with z=1 treatment and z=0 control

te

(ascendingly) ordered unique event times from both groups

eps

tolerence when comparing event times

Details

More details

Value

mfunc

various functions in column

Author(s)

Xiaodong Luo

Examples

ww<-wlrutil(y=c(1,2,3),d=c(1,0,1),z=c(1,0,0),te=c(1,3),eps=1.0e-08)
ww