Reporting of adverse drug events in the Veterans Health Administration for patients whose treatment with empagliflozin or apixaban was discontinued.

Purpose: To examine the reporting rates of adverse drug events (ADEs) with apixaban and empagliflozin as reports move up to the next level of spontaneous reporting. Methods: This was a retrospective cohort study of outpatients who discontinued apixaban or empagliflozin within 3 years of Food and Drug Administration (FDA) approval. We enriched the sample using an active surveillance strategy to identify subsets of patients with International Classification of Diseases (ICD) codes possibly associated with an ADE. Stratified random samples of charts were reviewed to determine if patients discontinued the medication due to an ADE. If so, we ascertained whether these were uploaded into the Veterans Administration (VA) electronic health record reporting system (Adverse Reaction Tracking System [ARTS]), VA national Web-based system (VA Adverse Drug Event Reporting System [VA ADERS]), and FDA MedWatch. Results: From the cohort of 2,973 patients who discontinued apixaban, 321 patients (10.8%) were randomly sampled for chart review (including 61 patients with relevant ICD codes). During chart review, 88 ADEs were identified, with 40/61 (65.6%) from the subset with ICD codes. Of the total of 88 ADEs, 18.2%, 10.2%, and 6.8% were reported in ARTS, VA ADERS, and MedWatch, respectively. Of the 1,555 patients who discontinued empagliflozin, 179 patients (11.5%) were randomly sampled for chart review (40 patients with relevant ICD codes). During chart review, 78 ADEs were identified, with 19/40 (47.5%) from the subset with ICD codes. Of the 78 ADEs, 28.2%, 19.2%, and 7.7% were reported in ARTS, VA ADERS, and MedWatch, respectively. Conclusion: We found substantial underreporting of apixaban and empagliflozin ADEs that became worse at each higher level of spontaneous reporting.