simPBC: simulating data alike the pbc data

In riskRegression: Risk Regression Models and Prediction Scores for Survival Analysis with Competing Risks

simulating data alike the pbc data

Description

This function can be used to simulate data alike the pbc data from the survival package.

Usage

simPBC(n)

Arguments

n	Sample size

Details

using lava to synthesize data

Value

The simulated data.

Author(s)

Thomas A. Gerds <[e-mail]>

Examples

library(survival)
library(lava)
# simulate data alike pbc data
set.seed(98)
d=simPBC(847)
d$protimegrp1 <- d$protimegrp=="10-11"
d$protimegrp2 <- d$protimegrp==">11"
d$sex <- factor(d$sex,levels=0:1,labels=c("m","f"))
sF1 <- survreg(Surv(time,status==1)~sex+age+logbili+protimegrp1+protimegrp2+stage3+stage4,
data=d)
coxF1 <- coxph(Surv(time,status==1)~sex+age+logbili+protimegrp1+protimegrp2+stage3+stage4,
data=d)
# load real pbc data
data(pbc,package="survival")
pbc <- na.omit(pbc[,c("time","status","age","sex","stage","bili","protime","trt")])
pbc$stage <- factor(pbc$stage)
levels(pbc$stage) <- list("1/2"=c(1,2),"3"=3,"4"=4)
pbc$logbili <- log(pbc$bili)
pbc$logprotime <- log(pbc$protime)
pbc$stage3 <- 1*(pbc$stage=="3")
pbc$stage4 <- 1*(pbc$stage=="4")
pbc$protimegrp <- cut(pbc$protime,c(-Inf,10,11,Inf),labels=c("<=10","10-11",">11"))
pbc$protimegrp1 <- pbc$protimegrp=="10-11"
pbc$protimegrp2 <- pbc$protimegrp==">11"
form1=Surv(time,status==1)~sex+age+logbili+protimegrp1+protimegrp2+stage3+stage4
F1 <- survival::survreg(form1,data=pbc)
form2=Surv(time,status==2)~sex+age+logbili+protimegrp1+protimegrp2+stage3+stage4
F2 <- survival::survreg(form1,data=pbc)
sF2 <- survreg(Surv(time,status==2)~sex+age+logbili+protimegrp1+protimegrp2+stage3+stage4,
data=d)
G <- survreg(Surv(time,status==0)~sex+age+logbili+protimegrp1+protimegrp2+stage3+stage4,
data=pbc)
sG <- survreg(Surv(time,status==0)~sex+age+logbili+protimegrp1+protimegrp2+stage3+stage4,
data=d)
# compare fits in real and simulated pbc data
cbind(coef(F1),coef(sF1))
cbind(coef(F2),coef(sF2))
cbind(coef(G),coef(sG))
cbind(coef(glm(protimegrp1~age+sex+logbili,data=pbc,family="binomial")),
coef(glm(protimegrp1~age+sex+logbili,data=d,family="binomial")))
cbind(coef(lm(logbili~age+sex,data=pbc)),coef(lm(logbili~age+sex,data=d)))

riskRegression documentation built on May 29, 2024, 10:59 a.m.