Working with EHR prescriptions. Issue arose about what is the correct value for days_supply when prescription has refills (this posting does not apply to fulfillment records). In Should days_supply and refills be included to calculate observation_period_end date?, @Klaus states: BTW: days_supply refers to a single prescription, it must not contain days from refills! Otherwise we would calculate a wrong daily dosage! If you want to record refills, use the drug_exposure_end_date. I would like to argue this is wrong for prescriptions.
Consider three example prescriptions, all of which we have seen in real records:
- Drug A once a day, 6 month supply, no refills
- Drug A once a day, 3 month supply, refill x 1
- Drug A once a day, 1 month supply, refill x 5 (edited to correct error in original post)
The controversy is: For these drug_exposure records, is âDays_Supplyâ 180, 90, and 30 respectively? Or is Days_Supply = 180 for all three? My reading of @Klausâs posting above is that he advocates 180, 90, 30. I am advocating 180 for all since it seems clear to me that the intent of all three prescriptions is to provide Drug A for 180 days. They just âget thereâ in different ways which will be reflected in the dispensing records (if you are lucky enough to have them which we donât). In all three cases, you will not expect to see a new prescription record for 180 days (assuming full compliance). If you use 180/90/30 days_supply, you could falsely generate disjoint drug_eras from the shorter prescriptions, which is (unfortunately) what we are generating.
Let the vehement conversations beginâŚ