[R] cumulative incidence plot vs survival plot

[array chip]

Thank you David. Didn't realized someone posted related topic this morning.

John



----- Original Message ----
From: David Winsemius <dwinsemius at comcast.net>
To: array chip <arrayprofile at yahoo.com>
Cc: r-help at 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 <dwinsemius at comcast.net>
> To: array chip <arrayprofile at yahoo.com>
> Cc: r-help at 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