[R] time-dependent covariate survival curves

[Hua Ding]

Dear r-users,

Does anyone know how to draw time-dependent survival curves?

Example:

Event outcome: CHD
Time-dependent covariate: NSAID use, which changes over time for each 
subject
I'm interested in survival curves stratified by NSAID use. 

I'd like to implement Simon & Makuch (1984) method. Is there a R 
package/function to draw this graph?


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Two related papers:

Simon R, Makuch RW. A non-parametric graphical representation of the
relationship between survival and the occurrence of an event:
application to responder versus non-responder bias.  Statistics in
Medicine 1984; 3: 35-44.

Schultz LR, Peterson EL, Breslau N. Graphing survival curve estimates
for time-dependent covariates.  Int'l J of Methods in Psychiatric
Research 2002; 11: 68-74.
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-- 
Rebecca Ding    Biostatistician II                     
School of Medicine
Department of Biostatistics   
Vanderbilt University
(W)615-343-3878