Abstract 9289: Use of Oral Anticoagulants for Atrial Fibrillation Drops by 20% Upon Entering the Medicare Coverage Gap

Abstract

Listen

Translate article

Introduction: Medicare Part D beneficiaries enter a coverage gap when prescription costs for a given year exceed $3300-3700. While in this gap, patients are responsible for a substantially increased portion of their medication costs until those costs exceed $4850-5000, at which time patients exit the coverage gap. For patients with atrial fibrillation (AF), the impact of this increased cost on oral anticoagulant (OAC) medication fills (“fills”) is unknown. Hypothesis: We hypothesized that for patients with AF who enter the coverage gap, OAC fills would decrease while in the gap, particularly for non-vitamin K antagonist OACs (NOACs) due to high costs. Methods: Using the Centers for Medicare and Medicaid Services claims data from 2016-2018, we assessed OAC fills (using proportion of days covered [PDC]) in patients with AF before, during, and after the coverage gap. We compared PDC for NOACs versus warfarin by coverage gap status. Results: We analyzed OAC PDC in patients with AF across 182,192 patient-years. For patients entering the gap, median time to enter was 174 days. For patients who entered and remained in the coverage gap, median PDC dropped significantly from 0.92 to 0.76 (p=<0.001) upon entering the coverage gap (Figure). For patients who entered and exited the coverage gap, PDC did not improve upon exiting the coverage gap, but rather continued to drop significantly despite having nearly full financial drug coverage (0.95 to 0.88 to 0.70; p=<0.001). This pattern was similar for patients on NOACs and on warfarin. Conclusions: Upon entering the coverage gap, OAC fills decrease significantly in patients with AF. In AF patients who exit the coverage gap, OAC fills do not increase but rather continue to decrease. This pattern was consistent for NOACs and warfarin. Coverage gap status may have important and persistent impacts on OAC use in patients with AF.