[R] help drawing kaplan-meier plot starting from 0

[Thomas Lumley]

On Thu, 16 Jan 2003, Frank Mattes wrote:

> Dear help news reader,
>
> I'm trying to draw a Kaplan-Meier curve and would like to ask the news
> group for some help
> Supposing I have study comapring two drugs, "A", and "B" and I recorde the
> time to get to the clinical endpoint (Time), in my case becommming virus free.
>
<various stufff>
> which gives me a Kaplan-Meier Curve, starting with 1. However I would like
> to the a plot
> starting with "0" and than showing the increasing numbers of patients
> becomming "virus negative".

You want the fun="event" option to plot.survfit.  Eg
       data(aml)
      leukemia.surv <- survfit(Surv(time, status) ~ x, data = aml)
# usual plot
      plot(leukemia.surv, lty = 2:3)
# cdf (event) ploot
      plot(leukemia.surv, lty = 2:3,fun="event")

	-thomas

Thomas Lumley			Asst. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle