It appears that the 2024 CumulativeMedicationDuration library for 2024 has some specific changes to the MedicationDispensedPeriod function. Specifically, the arguments to the Coalesce function for totalDaysSupplied reverses the 2023 arguments giving priority in 2024 to calculating based on supply, dosage, and frequency. In addition, the two clauses for the return are sequenced in reverse in 2024 which gives priority to using totalDaysSupplied instead of Dispense.RelevantPeriod, if that is available. With this change, the result is based specifically on the supply, dosage, and frequency when those data elements are available. Confusion on our part stems from understanding exactly what "dosage" represents.

In QDM5.5, dosage was defined as "Details of how medication is taken or is to be taken, i.e., the quantity (mg, cc, tablets) to be taken at a single administration."; in QDM5.6 dosage is defined as: "Quantity (e.g., mg, mL) of medication per unit.". This may appear to be similar, but there is now more ambiguity in the word "unit". Exactly what does this refer to? It seems that based on how CMD is calculated in the library, if a medication is a solution, then the amount of that solution per administration is dosage; example of 100ml supply and 5ml per day, means the dosage is 5ml and total days is 20. But in a quantity of capsules of 25mg each, taking 1 capsule/day is a dosage of 1 capsule and not 25mg. If this is the case, then it appears that mapping prescription data to dosage needs to be based on the SIG (i.e., 1 capsule per day) rather than on the strength of the medication taken per day. Can you clarify this?