documentation:next_cdm:days

End of a drug exposure

Proposals are now tracked as github issues

Requester: Klaus Bonadt, Christian Reich, Patrick Ryan
Discussion: here.

Proposal

Relevant table: http://www.ohdsi.org/web/wiki/doku.php?id=documentation:cdm:drug_exposure

Field	Required	Type	Description
drug_exposure_end_date	Yes	date	The end date for the current instance of Drug utilization. Depending on different sources, it could be a known or an inferred date and denotes the last day at which the patient was still exposed to drug.
days_supply	No	integer	The number of days of supply of the medication as prescribed. This reflects the intention of the provider for the length of exposure.
verbatim_end_date	No	date	The known end date of a drug exposure as provided by the source.

The verbatim_end_dat field is only necessary as the drug_exposure_end_date becomes mandatory, and might be (wrongly) inferred. In cases where no good data are available to fill that end_date, the ETL will have to take a guess, and that may not satisfy some algorithms for dose calculation.

Conventions

The drug_exposure_end_date denotes the day the drug exposure ended for the patient. This could be that the duration of drug_supply was reached (in which case drug_exposure_end_date = drug_exposure_start_date + days_supply -1), or because the exposure was stopped (medication changed, medication discontinued, etc.)

Use Cases

All standardized analytics and the drug era constructor will only use the drug_exposure_end_date. The days supply could be used to understand the intent of prescribing versus the reality, and it could be used to calculate MPR.