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# Cochran-Mantel-Haenszel Odds Ratios

I am completing a meta-analysis for my graduate thesis in Epidemiology and am attempting to find a CMH odds ratio for the relationship between Schizophrenia and 3q29 deletions.  I have written the code as:

proc freq data=schizophrenia3q292;
tables study*case*deldupcat / relrisk CMH;
title "3q29 Deletions and Duplications";
run;

with data in the form of:

studycat \$ case x n

with case=(0=control, 1=case), x=number of individuals with deletion and n=total number of individuals (cases or controls).

I followed that up with:

data schizophrenia1p362(drop=i);
length studycat \$20;
set schizophrenia1p36;
do i=1 to n;
if i<= x then deldupcat=1;
if i > x then deldupcat=0;
status=2-deldupcat;
output;
end;
run;

in order to create an observation for each individual (a pseudo-"studyid") in order to avoid using a weight.

While this is only one of several CNV's I am studying, I know, from a prior meta-analysis that the unadjusted odds ratio should be around 54 (mine is 55) and the CMH odds ratio should be around 41 (mine is 284!).  What could be causing my adjusted OR to be SO high?  Is this normal?  The previous meta-analysis used R instead of SAS.  But, this shouldn't cause such a discrepancy, should it?

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Posts: 13,542

## Re: Cochran-Mantel-Haenszel Odds Ratios

Without data it is hard to say specifically why any result is obtained. Comparison with another product or procedure and differences of result, assuming same data is used, often comes down to either different algorithms used or options that may be optional in one but defaut in the other. Again without seeing both code, and knowing both languages (I don't speak R for instance) it would be hard to say.

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Posts: 3

## Re: Cochran-Mantel-Haenszel Odds Ratios

[ Edited ]

Here is the data:

The first column is just the observation numbers assigned by SAS.  The second column is the study.  The fourth column identifies it as a deletion or duplication (I am just looking at deletions at the moment).  The fourth column identifies where it was a case (case=1) or control (case=0).  "X", or the fifth column, identifies how many cases or controls possessed this deletion, and the final column has the total number of cases or controls in the study.

Obs study location deldup case x n

 1 1 3q29 duplicat 1 3 420 2 1 3q29 duplicat 0 2 416 3 4 3q29 deletion 1 2 3391 4 4 3q29 deletion 0 0 3181 5 4 3q29 duplicat 1 0 3391 6 4 3q29 duplicat 0 1 3181 7 9 3q29 deletion 1 1 172 8 9 3q29 deletion 0 0 160 9 12 3q29 deletion 1 1 245 10 12 3q29 deletion 0 0 490 11 15 3q29 deletion 1 4 6882 12 15 3q29 deletion 0 0 6316 13 17 3q29 deletion 1 0 1438 14 17 3q29 deletion 0 1 33246 15 19 3q29 deletion 1 6 4719 16 19 3q29 deletion 0 0 5917 17 19 3q29 duplicat 1 1 4719 18 19 3q29 duplicat 0 0 5917 19 20 3q29 duplicat 1 10 8290 20 20 3q29 duplicat 0 0 7431 21 21 3q29 deletion 1 1 150 22 21 3q29 deletion 0 0 268 23 23 3q29 deletion 1 5 3945 24 23 3q29 deletion 0 0 3611 25 26 3q29 deletion 1 1 834 26 26 3q29 deletion 0 0 672 27 27 3q29 deletion 1 2 1259 28 27 3q29 deletion 0 0 1173

Hopefully this can help!

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Posts: 3