Stack multiple survival endpoints into a single survfit2 object

This function combines several survival endpoints from the same dataset by stacking them into a long format and fitting a single survfit object. It does not support competing risks models (i.e., when the event variable is a factor).

Usage

survfit_stack(data, surv_list)

Arguments

data

A data frame containing the survival variables.

surv_list

A named list where each element is a character vector of:

Length 2: time, event (for standard right-censored survival)
Length 3: time1, time2, event (for interval-censored survival and left truncation)

The names of the list elements will be used as a grouping variable in the output.

Value

A survfit object (or survfit2 if ggsurvfit is installed)

Examples

library(dplyr)
#> 
#> Attaching package: ‘dplyr’
#> The following objects are masked from ‘package:stats’:
#> 
#>     filter, lag
#> The following objects are masked from ‘package:base’:
#> 
#>     intersect, setdiff, setequal, union
set.seed(42)
df_surv = survival::lung %>%
  as_tibble() %>%
  mutate(
    time_os = time,
    event_os = status == 2,
    time_pfs = time / (1 + runif(n())),
    event_pfs = ifelse(runif(n()) > 0.3, event_os, 1),
    time_efs = time_pfs / (1 + runif(n())),
    event_efs = ifelse(runif(n()) > 0.3, event_pfs, 1)
  )

surv_list = list(
  "Overall survival" = c("time_os", "event_os"),
  "Progression-free survival" = c("time_pfs", "event_pfs"),
  "Event-free survival" = c("time_efs", "event_efs")
)

if(require("ggsurvfit")){

  df_surv %>%
    survfit_stack(surv_list=surv_list) %>%
    ggsurvfit() +
    add_confidence_interval() +
    add_risktable() +
    scale_ggsurvfit()

}
#> Loading required package: ggsurvfit
#> Loading required package: ggplot2
#> Warning: Function `survfit_stack()` (`?grstat::survfit_stack()`) is not yet validated
#> and may produce incorrect results.
#> ! Always double-check the results using your own code.
#> ℹ Please send your feedback to the grstat team.
#> This warning is displayed once every 8 hours.