There’s a bug in RxNorm Extension that was reported here.
The problem is missing links/attributes in the RxNorm Extension Standard concepts that are being lost (and not replaced by the RxNorm equivalents) during the process of RxNorm Extension to RxNorm ingredient replacement.
It affects cohorts since some of the Standard Drug concepts are not linked to their Ingredients in the CONCEPT_ANCESTOR table. And the cohorts built out of the ingredients (+ their descendants) may miss some concepts.
As for v20201222, the issue affects around 1% of concepts:
The full list of affected concepts:
Statistics:
list (click to expand)
| vocabulary_id | concept_class_id | count |
|---|---|---|
| RxNorm Extension | Branded Drug | 1207 |
| RxNorm Extension | Branded Drug Box | 1653 |
| RxNorm Extension | Branded Drug Comp | 1647 |
| RxNorm Extension | Branded Drug Form | 2343 |
| RxNorm Extension | Branded Pack | 1 |
| RxNorm Extension | Clinical Drug | 424 |
| RxNorm Extension | Clinical Drug Box | 1393 |
| RxNorm Extension | Clinical Drug Comp | 431 |
| RxNorm Extension | Clinical Drug Form | 136 |
| RxNorm Extension | Clinical Pack | 1 |
| RxNorm Extension | Marketed Product | 3889 |
| RxNorm Extension | Quant Branded Box | 544 |
| RxNorm Extension | Quant Branded Drug | 619 |
| RxNorm Extension | Quant Clinical Box | 700 |
| RxNorm Extension | Quant Clinical Drug | 723 |
While we’ll be fixing this, an additional review/search among the affected concepts is needed. Once you found the concept of interest in the list, add them manually to your cohorts.