R Under development (unstable) (2023-08-12 r84939 ucrt) -- "Unsuffered Consequences"
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> library(survival)
> #
> # check of the Surv2 function
> #
> # Build a flat form of the mgus2 data set.  Mix up the data set order, to test
> #  out that part of the underlying code.
> set.seed(1953)
> m2 <- mgus2[sample(1:nrow(mgus2), nrow(mgus2),replace=FALSE),]
> 
> temp1 <- data.frame(m2[,1:7], ftime=0)
> temp2 <- with(subset(m2, pstat==1), 
+               data.frame(id=id, ftime=ptime, event="progression"))
> 
> # competing risks: use only the first of death and progression
> temp3 <- with(subset(m2, pstat==0),
+               data.frame(id=id, ftime=futime, 
+                                 event=ifelse(death==0, "censor", "death")))
> mflat <- merge(temp1, rbind(temp2, temp3), all=TRUE)
> mflat$event <- factor(mflat$event, c("censor", "progression", "death"))
> 
> sfit1 <- survfit(Surv2(ftime, event) ~ sex, mflat, id=id)
> 
> # now compare it to the usual way
> etime <- with(mgus2, ifelse(pstat==1, ptime, futime))
> estat <- with(mgus2, ifelse(pstat==1, 1, 2*death))
> estat <- factor(estat, 0:2, c("censor", "progression", "death"))
> sfit2 <- survfit(Surv(etime, estat) ~ sex, mgus2)
> 
> all.equal(sfit1$pstate, sfit2$pstate)
[1] TRUE
> 
> # Cox model
> cfit1 <- coxph(Surv2(ftime, event) ~ sex + age, data=mflat, id=id)
> cfit2 <- coxph(Surv(etime, estat)  ~ sex + age, data=mgus2, id=id)
> all.equal(cfit1[c("coefficients", "var", "loglik", "score")],
+           cfit2[c("coefficients", "var", "loglik", "score")])
[1] TRUE
> 
> # And using the explicit call to build a data set
> sdata <- Surv2data(Surv2(ftime, event) ~ ., data=mflat, id=id)
> cfit3 <- coxph(Surv2.y ~ sex + age, data=sdata, id=id)
> all.equal(cfit1[c("coefficients", "var", "loglik", "score")],
+           cfit3[c("coefficients", "var", "loglik", "score")])
[1] TRUE
> 
> # Create a data set with error = two events on the same day
> #  A model with this data will generate an error.
> temp4 <- with(m2, 
+               data.frame(id=id, ftime=futime, 
+                                 event=ifelse(death==0, "censor", "death")))
> mflat2 <- merge(temp1, rbind(temp2, temp4), all=TRUE)
> mflat2$event <- factor(mflat2$event, c("censor", "prog", "death"))
> stemp <- survcheck(Surv2(ftime, event) ~ sex, data=mflat2, id=id)
> all.equal(stemp$duplicate$row, which(duplicated(mflat2[,c("id", "ftime")])))
[1] TRUE
> 
> # Full 3 state model.  We need to make progressions that are tied with
> #  deaths be just a bit sooner.
> temp2b <- with(subset(m2, pstat==1),
+                data.frame(id=id, ftime= ifelse(ptime==futime & death==1, ptime-.1, ptime),
+                event="progression"))
> temp3b <- with(m2,
+                data.frame(id=id, ftime=futime, event=ifelse(death==0, "censor", "death")))
> 
> mflat3 <- merge(temp1, rbind(temp2b, temp3b), all=TRUE)
> mflat3$event <- factor(mflat3$event, c("censor", "progression", "death"))
> 
> cfit4 <- coxph(Surv2(ftime, event) ~ sex + age + mspike, mflat3, id=id)
> 
> # For a standard start-stop data set use tmerge
> m3 <- tmerge(m2[,1:7], subset(m2,,c(id, futime, death)), id=id, 
+                                   event= event(futime, 2*death))
> m3 <- tmerge(m3, temp2b, id=id, event= event(ftime))
> m3$event <- factor(m3$event, 0:2, c("censor", "progression", "death"))
> cfit5 <- coxph(Surv(tstart, tstop, event) ~ sex + age + mspike, m3, id=id)
> 
> all.equal(cfit4[c("coefficients", "var", "loglik", "score")],
+           cfit5[c("coefficients", "var", "loglik", "score")])
[1] TRUE
> 
> 
> proc.time()
   user  system elapsed 
   1.31    0.14    1.45