How to get 95% CI from R's coxph?

Question

I have used the following function in R's coxph() to fit a cox hazard model. I want to report the proper statistics; however, there is no 95% CI in the output.

Surv(days, censor) ~ gender + age + treatment, data_1)

I only get the following columns.

coef exp(coef) se(coef) z p

Solution

If you need this for further processing, consider a tidy solution with broom:

library(broom)
library(dplyr)
library(survival)

mod <- coxph(Surv(time, status) ~ sex + age, data = lung)

mod |> 
  tidy(conf.int = TRUE, exponentiate = TRUE) |> 
  select(term, estimate, starts_with("conf"))

#> # A tibble: 2 x 4
#>   term  estimate conf.low conf.high
#>   <chr>    <dbl>    <dbl>     <dbl>
#> 1 sex      0.599    0.431     0.831
#> 2 age      1.02     0.999     1.04

More details at this reference