RE: [NMusers] COX Proportional Hazard Model with Time Dependent Covariate

 
Hi, Nuwan,
 
Just want to share what I just have found how to do it with S-pus for my
#2 question. It is easier to illustrate with an example.
 
 
data.cov <-data.frame(start=c(0, 1, 2, 3), stop=c(1, 2, 3, 4),
event=c(0, 0, 0, 1), age=(22, 23, 24, 25), transplant.surgery=c(0, =
0, 1,
1), weight=c(70, 70, 69, 69))
survfit(your.previous.fit.outcome, data.cov, individual=T)
 
Here, "age", "transplant.surgery", and "weight" are the time-dependent
covariates that have been used to obtain "your.previous.fit.outcome".
It means that corresponding to time 0-1, age=22, =
transplant.surgery=0,
weight=70l; corresponding to time 1-2, age=23, =
transplant.surgery=0,
weight=70 ... .
 
Very important, the projected survival can only be obtained by flagging
"individual=T".
 
Cheers!
 
 
Liang

________________________________

From: Nanayakkara, Nuwan [mailto:Nuwan.Nanayakkara_at_amylin.com]
Sent: Tuesday, July 03, 2007 1:54 PM
To: Zhao, Liang; nmusers_at_globomaxnm.com
Subject: RE: [NMusers] COX Proportional Hazard Model with Time Dependent
Covariate


For (2), take a look at Survival Analysis Using SAS: A Practical Guide:
Books: Paul D. Allison by Paul D. Allison.


________________________________

From: owner-nmusers_at_globomaxnm.com [mailto:owner-nmusers_at_globomaxnm.com]
On Behalf Of Zhao, Liang
Sent: Monday, July 02, 2007 2:34 PM
To: nmusers_at_globomaxnm.com
Subject: [NMusers] COX Proportional Hazard Model with Time Dependent
Covariate


Dear All,
 
I have the following questions regarding with COX survial model with
Time Dependent Covariate that needs your experience and expertise
 
(1) Even we can do it with S-Plus or SAS, it can not be handled by
NONMEM, am I right? If I am wrong, who has started the work?

(2) How to make predictions with time-variant covariates based on COX
model using S-plus or SAS, if not NONMEM?
 
The question is asked because certain epidemic diseases are
season-sensitive and none assumption on base hazard is advantageous over
parametric approaches. Thank you in advance!
 
Liang Zhao

Received on Tue Jul 03 2007 - 15:41:17 EDT