I am trying to calculate the overlapping days between 2 drugs to get an accurate reflection of days supply. I don't even know if this is possible but I figured I'd ask.
Here is an example of what we need to be able to do if Drug A and Drug B are in the same drug class:
Drug A claim dates: 8/01/17 X 30 day supply
9/01/17 X 30 day supply
10/01/17 X 30 day supply
Drug B claim dates: 9/5/17 X 30 day supply
10/5/17 X 30 day supply
Adding Drug A + Drug B claims would = 150 days, but that is not a correct reflection of days they are receiving therapy with drugs in the same drug class.
Accurate reflection would be: (Drug A 90 days + Drug B 60 days) minus 55 days overlap where patient is receiving both Drug A + Drug B, so total days of therapy is more accurately 95 days.
Does anyone have any ideas on how to do this? Thank you!