On Jun 27, 2011, at 5:04 PM, array chip wrote:
Hi David,
Thanks for responding, and plain text ...(didn't realized I was in
rich text).
The endpoint is disease recurrence, I was producing a regular KM
plot of
recurrence-free probability. Then someone recommend using cumulative
incidence
is preferred because death was censored in the dataset. I did a
little googling,
I found CI was used often in the context of competing risk. I am
totally new to
competing risk and trying to understand what competing risk means
and why CI is
preferred than KM survival in this context. If you could share your
thoughts
helping me to understand, greatly appreciated.
Searched archive, found people talking about cmprsk package for
estimating and
plotting CI. would that be the same as the code you suggested:
plot(time,
cumsum(dead))
I do not think it would. I think this morning's post from Dr Geskus is
on point here. You should read his 2011 'Biometrics' paper.
--
David.
Thanks very much!
John
________________________________
From: David Winsemius <dwinsem...@comcast.net>
To: array chip <arrayprof...@yahoo.com>
Cc: r-help@r-project.org
Sent: Mon, June 27, 2011 1:45:35 PM
Subject: Re: [R] cumulative incidence plot vs survival plot
On Jun 27, 2011, at 4:31 PM, array chip wrote:
Hi, I am wondering if anyone can explain to me if cumulative
incidence (CI) is
just "1 minus kaplan-Meier survival"?
First tell us what you think CI is defined as. I suspect it is not
the same. The
KM estimator is cumulative product of (alive-n(dead))/alive so is
the product of
interval survival probabilities. I doubt that your definition of CI
has a
similar denominator.
Under what circumstance, you should use
cumulative incidence vs KM survival? If the relationship is just CI =
1-survival, then what difference it makes to use one vs. the other?
And in R how I can draw a cumulative incidence plot.
plot(time, cumsum(dead)) ...?
I know I can make a
Kaplan-Meier survival plot using plot(survfit()), for example:
fit<-survfit(Surv(time,status)~group,data=data)
plot(fit, col=1:2)
How to draw CI plot then?
As above. Specify what you are seeking.
There is a well-defined relationship between S(t) and the cumulative
hazard.
Maybe you should do a little study of those terms in texts regarding
survival
analysis.
Thanks very much!
John
[[alternative HTML version deleted]]
Isn't it time you learned to post in plain text?
--
David Winsemius, MD
West Hartford, CT
David Winsemius, MD
West Hartford, CT
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