a_DCI_PD_STS_v1

km <- survfit(Surv(last.fu, death)~trt, data=dat)

km

## Call: survfit(formula = Surv(last.fu, death) ~ trt, data = dat)
## 
##            n events median 0.95LCL 0.95UCL
## trt=FALSE 62     44   4.52    3.75    9.56
## trt=TRUE  66     38   6.84    4.47   10.20

plot(km, col=c("blue", "red"))
legend("topright", c("non-STS", "STS"), lty=1, col=c("blue", "red"))

fit <- coxph(Surv(last.fu, death)~trt, data=dat)
summary(fit)

## Call:
## coxph(formula = Surv(last.fu, death) ~ trt, data = dat)
## 
##   n= 128, number of events= 82 
## 
##            coef exp(coef) se(coef)     z Pr(>|z|)
## trtTRUE -0.1049    0.9004   0.2233 -0.47    0.639
## 
##         exp(coef) exp(-coef) lower .95 upper .95
## trtTRUE    0.9004      1.111    0.5812     1.395
## 
## Concordance= 0.517  (se = 0.032 )
## Rsquare= 0.002   (max possible= 0.994 )
## Likelihood ratio test= 0.22  on 1 df,   p=0.6383
## Wald test            = 0.22  on 1 df,   p=0.6386
## Score (logrank) test = 0.22  on 1 df,   p=0.6384