|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.
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.