Programming the statistical procedures from SAS

Testing for effect modification across race (4 strata) in Cox proportional model

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Contributor
Posts: 34

Testing for effect modification across race (4 strata) in Cox proportional model

Hello,

I am running Cox regression and wanted to test effect modification across race (4 strata). This is the code I am using:

 

proc phreg data = ABC;
model asthmatt*asthma(0) = p_cvscore  tp_cvscore/risklimit;
tp_cvscore=p_cvscore*log(asthmatt);
test_proportionality: test p_cvscore, tp_cvscore;
run;
 
Is testing for effect modification the same for proportionality assumption? I need explanation and if my code correct or wrong, please. Assuming the test is approriate in this case, what other options to use if the test of proportionality was sig? I mean what to do, what statistical solutions should I proceed with?
Thanks,
 
Contributor
Posts: 34

Re: Testing for effect modification across race (4 strata) in Cox proportional model

To add, I got this error message (log says  P_CVSCORE in TEST statement test_proportionality is not a parameter in the model) when I used this code:

 

proc phreg data = ABC;
class p_cvscore race1c education salary ;
model asthmatt*asthma(0) = p_cvscore  tp_cvscore /risklimit;
tp_cvscore=p_cvscore*log(asthmatt);
test_proportionality: test p_cvscore, tp_cvscore;
run;

 

 

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