This works, thank you so much!   Just one more question - not sure if this is possible to incorporate it in the code (and if it is not, I can just make a separate dataset for this) - but for patients who have had only 1 prescription, it marks the sum_days_supply as missing since that is what we have assigned it to do.    Would it be easier if I just ouput all these patients to a separate dataset and then set the 2 data sets later?     ... View more

Hello batulelec,   Welcome to the SAS Data Management Community. I'm glad you found some useful info! If one of the replies was the exact solution to your problem, can you "Accept it as a solution"? Or if one was particularly helpful, feel free to "Like" it. This will help other community members who may run into the same issue know what worked.   Thanks! Laura ... View more