## S3 method for class 'survfit':
print(x, scale=1,digits = max(options()$digits - 4,
3), print.n=getOption("survfit.print.n"), show.rmean=getOption("survfit.print.mean"),...)survfit function.scale=365 would scale the printout to years.x, with the invisible flag set.rmean) and its standard error, and the median survival
with its confidence interval are printed. If there are multiple curves, there is one line of output for each.rmean) and its standard error se(rmean) are based on a truncated estimator. If the
last observation(s) is not a death, then the survival curve estimate does not
go to zero and the mean survival time cannot be estimated. Instead, the
quantity reported is the mean of survival restricted to the time before
the last censoring. When the last censoring time is not random this
quantity is occasionally of interest.Any randomness in the last censoring time is not taken into account in computing the standard error of the restricted mean. The restricted mean is shown mainly for compatibility with S, and may not be shown by default in future versions.
The median and its confidence interval are defined by drawing a horizontal line at 0.5 on the plot of the survival curve and its confidence bands. The intersection of the line with the lower CI band defines the lower limit for the median's interval, and similarly for the upper band. If any of the intersections is not a point, then we use the smallest point of intersection, e.g., if the survival curve were exactly equal to 0.5 over an interval.
The "number of observations" is not well-defined for counting process data. Previous versions of this code used the number at risk at the first time point. This is misleading if many individuals enter late or change strata. The original S code for the current version uses the number of records, which is misleading when the counting process data actually represent a fixed cohort with time-dependent covariates.
Four possibilities are provided, controlled by print.n or by
options(survfit.print.n): "none" prints NA,
"records" prints the number of records, "start" prints the
number at the first time point and "max" prints the maximum
number at risk. The initial default is "start".
summary.survfit, survfit.object, survfit##effect of print.n and show.rmean
data(heart)
a<-coxph(Surv(start,stop,event)~age+strata(transplant),data=heart)
b<-survfit(a)
print(b,print.n="none")
print(b,print.n="records")
print(b,print.n="start")
print(b,print.n="max")
print(b,show.rmean=FALSE)Run the code above in your browser using DataLab