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How to store medication dose and/or quantity in Drug_Exposure table

Implementers
#1

I apologize for any duplication of effort, but I have been researching the forums looking for the topic on the accurate population of the prescribed dosage from a drug order. I have seen references to attributes coming and going over the past 3 years. The existing posts have solutions that rely on columns such as effective_drug_dose or dose_unit_concept_id that were removed only to be requested again later.

We are taking prescriptions from the order entry system in the pharmacy and ultimately persisting them into OMOP in real time. In this type of live processing we don’t have the ability to perform extensive ETL that brings in other sources and possibly human intervention. The goal is to land the data and then post-process the data to prepare it for analysis.

The drug_exposure table as of V5.3 (current version is 6) included quantity (which is not dose) and dose_unit_source_value (which is not the unit associated with quantity).
The effective_drug_dose and dose_unit_concept_id were removed. By association the dose_unit_source_value should have also been removed because it was associated with dose_unit_concept_id. There has been discussion of a field called quantity_unit_concept_id but I have never found such a field in any historical CDM documentation.

While I can add fields and populate them locally, it won’t help downstream processing because the Atlas tooling in any release relies on the OMOP core schema.

In case you are curious, my sources are HL7v2 RDE Medication Orders, HL7v2 RAS Medication Administrations, HL7v2 DFT Detailed Financial Transactions (for MAR events), HL7 FHIR MedicationRequest and MedicationAdministration resources. All of these HL7 source standards have a medication dose, rate, and quantity as individual elements with related units. I’m looking for how these map to the Drug_Exposure table and I am having problems.

Thanks,
Jeff

#2

Not knowing the exact issues with the data, I can give you the general notion of how it works now (neither a perfect solution nor a generalizable one):
quantity field is basically all that you need. Say, you have an ingredient, its dosage and quantity:
aspirin 325 mg 1 tab per day.
The proper way is to map it to RxNorm concept 19082433 Aspirin 325 MG and put 1 in quantity (as for solid drugs quantity represents the number of pills/capsules etc).
Second example:
heparin 0.25 units per ml, 3 ml
Then, again, you map to 43011613 heparin sodium, porcine 0.25 UNT/ML and put 3 in quantity (as for liquid drugs you store the number of milliliters or another measure of volume).
For infusion rates we had a couple of pretty intense discussions and seems like folks ended up using the approaches that fitted their workflows and needs. My suggestion was to put the rate into the quantity field and the unit (mg/hour or something) into the dose_unit_source_value. You may also refer to this post: How to record an inpatient drug infusion?.

Does it make sense?

#3

@jsjacobs:

Add-on to what @aostropolets said:

Yes, we have been flipping back and forth on that. On one hand, we want to be able to capture dose where we have it, e.g. chemo. On the other hand, we don’t want the same information to appear twice (and inevitably contradict each other, as it always does when you do that). And it might be awkward to present the actual dose in the current model, which is built for cases where we only know the intended dose from quantity, product strength and sig.

It should be all described here. Does that not work?

t