rmstutil: A utility function to calculate the true restricted mean...

In PWEALL: Design and Monitoring of Survival Trials Accounting for Complex Situations

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

PWEALL documentation built on Aug. 9, 2023, 9:08 a.m.