rmstpower: Calculate powers at different cut-points based on difference...

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

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 \lambda(t)=\sum_{j=1}^m \lambda_j I(t_{j-1}\le t<t_j), where \lambda_1,\ldots,\lambda_m are the corresponding elements of the rates and t_0,\ldots,t_{m-1} are the corresponding elements of tchange, 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)

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