Kaplan-Meier survival fit with attainment-time summary

Fits a Kaplan-Meier estimator with survival::survfit, optionally stratified by a grouping variable, and returns the median and quartile attainment times with their confidence intervals.

Usage

survivalFit(
  data,
  time = "time",
  event = "event",
  group = NULL,
  conf_level = 0.95
)

Arguments

data: A data.frame with the survival columns.
time, event: Column names of the follow-up time and the event indicator (1 = event, 0 = censored).
group: Optional grouping-variable column name for stratified curves.
conf_level: Confidence level (default 0.95).

Value

An object of class physio_km (a list) with fit (the survfit), quantiles (median / Q1 / Q3 attainment times with CIs, per group) and summary table, plus print and plot methods.

References

Kaplan EL, Meier P (1958). Nonparametric estimation from incomplete observations. JASA, 53(282), 457-481.

Examples

if (requireNamespace("survival", quietly = TRUE)) {
  survivalFit(survival::lung, "time", "status", group = "sex")
}
#> Kaplan-Meier fit
#> Call: survfit(formula = form, data = data, conf.int = conf_level)
#> 
#>         n events median 0.95LCL 0.95UCL
#> sex=1 138    112    270     212     310
#> sex=2  90     53    426     348     550
#> 
#> Attainment times (median / quartiles):
#>  group  Q1 median  Q3 median_lower median_upper
#>  sex=1 144    270 457          212          310
#>  sex=2 226    426 687          348          550