An object of class 'surv_summary', which is a data frame with
the following columns:
time: the time points at which the
curve has a step.
n.risk: the number of subjects at risk at t.
n.event: the number of events that occur at time t.
n.censor: number
of censored events.
surv: estimate of survival.
std.err:
standard error of survival.
upper: upper end of confidence interval.
lower: lower end of confidence interval.
strata: stratification of survival curves.
In a situation, where survival curves have been fitted with one or more
variables, surv_summary object contains extra columns representing the
variables. This makes it possible to facet the output of
ggsurvplot
by strata or by some combinations of factors.
surv_summary object has also an attribut named 'table' containing
information about the survival curves, including medians of survival with
confidence intervals, as well as, the total number of subjects and the
number of event in each curve.