pwecxpwufindt: calculate the timeline when certain number of events...

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

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

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

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