Trends and Variation in Oral Anticoagulant Choice in Patients with Atrial Fibrillation, 2010–2017

Objective: Since 2010, several non–vitamin K antagonist oral anticoagulants (NOACs) have been brought to the U.S. market, yet little is known regarding their evolving adoption for prophylaxis of atrial fibrillation (AF)-related stroke. We examined temporal trends in choice of oral anticoagulants (OACs) among incident OAC users with AF and its association with patient demographic and clinical characteristics. Methods: We conducted a serial cross-sectional analysis of medical and pharmacy claims for commercial and Medicare Advantage enrollees in a large, private, U.S. health plan. We identified 112,187 adults with nonvalvular AF starting OACs between October 2010 and March 2017. Multivariable logistic regression was used to examine the associations of patient characteristics with prescription of NOACs versus warfarin. Multinomial logistic regression was used to test the associations of patient characteristics with choice among NOACs. Results: The prescription of NOACs has increased dramatically since their introduction in October 2010. In the first quarter of 2017 (2017Q1), 7502 patients started OACs, of whom 78.9% used NOACs and 21.1% warfarin. For NOACs, 3.8% used dabigatran, 25.0% rivaroxaban, and 50.1% apixaban. In multivariable analyses, factors associated with choice of NOACs versus warfarin included younger age, lower stroke or bleeding risk, fewer comorbidities, higher education level or household net worth, and prescription by cardiologists (all p<0.001). There was no sex difference in likelihood of filling NOACs versus warfarin in 2010Q4–2012, but women had higher odds of starting NOACs (odds ratio = 1.19; 95% confidence interval = 1.14–1.25) in 2015–2017Q1. Among NOAC users, the odds of apixaban prescription increased with age, female sex, stroke or bleeding risk, and comorbidities (all p<0.05). Conclusion: NOAC prescriptions have increased substantially among incident OAC users with nonvalvular AF, predominantly driven by increased prescription of apixaban. Warfarin and apixaban were generally preferred for elderly patients, patients with higher stroke or bleeding risk, and patients with more comorbidities.