Thank you for this suggestion, I did add an interaction term for OLTPA*TIME, it is significant. I wanted to verify a couple of things. 1) Because OLTPA is a categorical variable it should be included in the class statement which gives separate effect estimates for each OLTPA category in the outcomes. The same would be true for any categorical covariates I include? 2) I thought that proc glimmix would include each participant regardless of whether data was missing (i.e. maximizes data use), but I noticed in the output it is not using all cases as the "caseid" degrees of freedom is much smaller than my actual sample.
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