simdataKM | R Documentation |
Simulated data to use in a Kaplan-Meier STEPP analysis.
data(simdataKM)
A data.frame
object with columns:
time-to-event data
censoring indicator
treatment indicator
covariate values
### the following code generates the data in the object ### set.seed(101) n <- 1000 # generate the treatment indicator Txassign <- sample(c(1, 2), n, replace = TRUE, prob = rep(.5, 2)) n1 <- sum(Txassign == 1) n2 <- n - n1 # generate the covariate values mean_cov <- 55 sd_cov <- 7 covariate <- rnorm(n, mean = mean_cov, sd = sd_cov) # generate the survival times and censoring indicator assuming a treatment-covariate interaction Entry <- sort(runif(n, 0, 5)) SurvT1 <- .5 beta0 <- -65/75 beta1 <- 2/75 Surv <- rep(0, n) lambda1 <- -log(SurvT1)/4 Surv[Txassign == 1] <- rexp(n1, lambda1) Surv[Txassign == 2] <- rexp(n2, (lambda1*(beta0 + beta1*covariate[Txassign == 2]))) EventTimes <- rep(0, n) EventTimes <- Entry + Surv censor <- time <- rep(0, n) for (i in 1:n) { censor[i] <- ifelse(EventTimes[i] <= 7, 1, 0) time[i] <- ifelse(EventTimes[i] < 7, Surv[i], 7 - Entry[i]) } simdataKM <- data.frame(time = time, censor = censor, trt = Txassign, covar = covariate) # overall survival analysis simdataKM_surv <- Surv(simdataKM$time, simdataKM$censor) simdataKM_fit <- survfit(simdataKM_surv ~ trt, data = simdataKM) plot(simdataKM_fit, lty = 2:3, lwd = rep(2, 2), col = 2:3) legend("topright", c("Treatment 1", "Treatment 2"), lty = 2:3, lwd = rep(2, 2), col = 2:3) title("Kaplan-Meier Curves\nfor simulated data") survdiff(simdataKM_surv ~ trt, data = simdataKM, rho = 0)
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