One of the items that came out of the OHDSI Symposium THEMIS Working Group meeting was what to do if multiple drugs are reported on the same day. Over the years of OHDSI this is a common question that gets asked and an answer that could also apply to procedures.
If a patient has multiple records on the same day for the same drug or procedures the ETL should not dedupe them unless there is probable reason to believe the item is a true data duplicate.
Work with Clair to have posted on the DRUG_EXPOSURE & PROCEDURE_OCCURRENCE page under the CDM Wiki.
We are planning on bringing this up Day 1 of the THEMIS F2F. We welcome any thoughts or comments.