mydat=structure(list(Biliary.Anast.Stricture = structure(c(1L,1L,2L,1L),.Label = c("No","Yes"),class = "factor"),TIME = c(98,93,11,86,69,81,50,34,46,75,77,54,90,15,60,13,89,83,88,40,0.2,12,7,80,65,52,66,4,82,67,68,79,70,76,74,71,72,49,59,5,44,55,64,62,26,17,14,57,33,24,19,51,27,30,28,39,48,53,37,58,42,56,38,35,16,3,18,8,43,25,41,29,21,32,2,6,22,23,10,10),Censured.for.stricture. = structure(c(1L,.Label = c("censored","COMPLETE"),class = "factor")),class = "data.frame",row.names = c(NA,-207L))

我这样做

library("survival")
library("survminer")
> fit <- survfit(Surv(TIME,Censured.for.stricture.) ~ Biliary.Anast.Stricture,data=mydat)
> fit
Call: survfit(formula = Surv(TIME,data = mydat)

并且您可以看到，中位数的计算方式不像0.95 CI

                              n events median 0.95LCL 0.95UCL
Biliary.Anast.Stricture=No  187      0     NA      NA      NA
Biliary.Anast.Stricture=Yes  20     20      5       4      11

我如何理解为什么不计算中位数和CI？我认为我的数据集结构正确，但是如果我写错了，请建议我该怎么做！