Thank you David. Didn't realized someone posted related topic this morning.
John ----- Original Message ---- From: David Winsemius <dwinsem...@comcast.net> To: array chip <arrayprof...@yahoo.com> Cc: r-help@r-project.org Sent: Mon, June 27, 2011 3:38:36 PM Subject: Re: [R] cumulative incidence plot vs survival plot 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 ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
