Simulates data that looks like fit from Cox model. Censor data automatically for highest value of the event times by using cumulative hazard.
sim.cox(cox,n,data=NULL,cens=NULL,rrc=NULL,entry=NULL,...)Arguments
- cox
output form coxph or cox.aalen model fitting cox model.
- n
number of simulations.
- data
to extract covariates for simulations (draws from observed covariates).
- cens
specifies censoring model, if "is.matrix" then uses cumulative hazard given, if "is.scalar" then uses rate for exponential, and if not given then takes average rate of in simulated data from cox model.
- rrc
possible vector of relative risk for cox-type censoring.
- entry
delayed entry variable for simulation.
- ...
arguments for rchaz, for example entry-time
Examples
data(sTRACE)
cox <- coxph(Surv(time,status==9)~vf+chf+wmi,data=sTRACE)
sim1 <- sim.cox(cox,1000,data=sTRACE)
cc <- coxph(Surv(time,status)~vf+chf+wmi,data=sim1)
cbind(cox$coef,cc$coef)
#> [,1] [,2]
#> vf 0.2970218 0.4662516
#> chf 0.8018334 0.7656359
#> wmi -0.8920005 -0.6820267
cor(sim1[,c("vf","chf","wmi")])
#> vf chf wmi
#> vf 1.0000000 0.1467306 -0.1267284
#> chf 0.1467306 1.0000000 -0.4059362
#> wmi -0.1267284 -0.4059362 1.0000000
cor(sTRACE[,c("vf","chf","wmi")])
#> vf chf wmi
#> vf 1.00000000 0.1346711 -0.08966805
#> chf 0.13467109 1.0000000 -0.37464791
#> wmi -0.08966805 -0.3746479 1.00000000
cox <- phreg(Surv(time, status==9)~vf+chf+wmi,data=sTRACE)
sim3 <- sim.cox(cox,1000,data=sTRACE)
cc <- phreg(Surv(time, status)~vf+chf+wmi,data=sim3)
cbind(cox$coef,cc$coef)
#> [,1] [,2]
#> vf 0.2970218 0.3234739
#> chf 0.8018334 0.7634755
#> wmi -0.8920005 -0.7312587
plot(cox,se=TRUE)
plot(cc,add=TRUE,col=2)
cox <- phreg(Surv(time,status==9)~strata(chf)+vf+wmi,data=sTRACE)
sim3 <- sim.cox(cox,100,data=sTRACE)
cc <- phreg(Surv(time, status)~strata(chf)+vf+wmi,data=sim3)
cbind(cox$coef,cc$coef)
#> [,1] [,2]
#> vf 0.2907750 -0.8705529
#> wmi -0.8905339 -0.7120919
plot(cox)
plot(cc,add=TRUE,col=2)
