Abstract 231: Racial and Ethnic Disparities in Anticoagulant Choice for Atrial Fibrillation in the Veterans Health Administration: Results From the REACH AF Study

Background: Atrial fibrillation (AF) affects nearly 1 million patients in VA, with morbidity and mortality disproportionately affecting racial/ethnic minorities. Anticoagulation reduces stroke risk in AF, yet warfarin and direct oral anticoagulants (DOACs) are underused in minorities. We compared anticoagulant initiation by race/ethnicity for patients with AF in VA—which facilitates access to medications through a uniform drug formulary.

Methods: Using the VA Corporate Data Warehouse, we identified patients from 1/1/2014 – 12/31/2018 with an AF diagnosis and a confirmatory diagnosis ≦180 days of their index AF diagnosis. We excluded patients with an AF diagnosis or anticoagulant therapy in the 2 years prior to their index AF diagnosis, as well as those with valvular heart disease, who died within 180 days of AF diagnosis, or had missing or “other” race/ethnicity. We categorized our independent variable as non-Hispanic white (NHW), non-Hispanic black (NHB), and Hispanic. Our primary outcome was receipt of any anticoagulant ≦180 days of AF diagnosis as well as the type of anticoagulant (warfarin, DOAC) initiated. We used logistic regression to compare outcomes by race/ethnicity, adjusting for year of diagnosis, stroke risk with CHADS2VA2Sc score, renal disease, region and rurality.

Results: We identified 148,062 patients with incident AF: 8.6% were NHB, 3.4% Hispanic. Overall, NHBs (57.7%) and Hispanics (58.4%) were less likely than NHWs (61.4%) to initiate any anticoagulant therapy (p <0.01), driven by lower DOAC initiation for minorities (36.8% NHBs, 36.5% Hispanics, 43.0% NHWs; p <0.01). Compared to NHWs, the adjusted odds ratios (AORs) for receiving any anticoagulant or DOACs were significantly lower for NHBs and Hispanics (Table); in contrast, AORs for receiving warfarin were significantly higher among minorities. As DOAC initiation increased from 16.8% (2014) to 60.3% (2018), racial disparities in initiation increased from 1.7 to 9.1% for NHBs vs. NHWs and from 0.9 to 9.4% for Hispanics vs. NHWs.

Conclusions: In a national cohort of AF in VA, we identified significant racial/ethnic disparities in anticoagulant initiation, driven by growing disparities in DOAC initiation. Understanding these differences is essential to ensuring equitable AF care in the largest U.S. integrated health care system.