I would certainly start with PROC GEE, as Rick states, and in particular I would look at this example in the documentation:
http://support.sas.com/documentation/cdl/en/statug/68162/HTML/default/viewer.htm#statug_gee_examples05.htm
More generally, I would use PROC GLIMMIX, and treat the data as coming from a multinomial distribution. However, in GLIMMIX as opposed to GEE, the model will be fit as conditional on the random effect, rather than as a marginal over the random effect (which is time in this case). The marginal log odds ratios will tend to be biased toward the mean compared to the conditional log odds ratios.
Steve Denham
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