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Calcite | Level 5

I have an GLM and a treament variable given to the patient in a factorial fashion coded in the following manner


2-oral drug A

3-inhaler B

4-drug A and B togther


My outcome variable is the weekly number of puffs of albuterol taken for the patient's asthma.


I need to test whether the treatment effect, which is significant in my model, can be attributed entirely to the inhaler B. Can someone help me in how I might test this in SAS? Would it be some sort of contrast statement? Thanks all.

Jade | Level 19

Unfortunately, this experimental design isn't really a factorial, as each patient proceeds through the four treatments in the same order.


In that sense, this is a repeated measures design, with a response variable that is a count.  In order to get the comparisons you want, you'll likely want to use PROC GLIMMIX.


Try the following for a comparison of the marginal estimates:

proc glimmix data=yourdata;
class ID treatment;
model count = treatment / dist=poisson;
random treatment / residual type=un subject=ID;
lsmeans treatment / diff;

This should at least get you started.  There may be some glitches along the way as far as convergence, etc., but those can be dealt with.


Steve Denham






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