Background: Medication nonadherence predicts poor outcomes among patients with non-valvular atrial fibrillation (NVAF). Understanding differences in adherence rates among non-vitamin K oral anticoagulants (NOACs) could guide treatment decisions, promote adherence and improve clinical outcomes.
Objective: To compare adherence to rivaroxaban and apixaban among the overall NVAF population and subgroups at higher risk for adverse clinical outcomes (e.g., prior OAC use, multiple comorbidities, and with risk factors for nonadherence).
Methods: Using healthcare claims from the Truven Health Analytics MarketScan database from 7/2012-7/2015, adult patients with 2 dispensings of rivaroxaban or apixaban at least 180 days apart, with > 60 days of supply, ≥ 6 months of pre- and post-index eligibility, ≥ 2 atrial fibrillation diagnoses pre- or post-index, and without valvular involvement were identified. Propensity score methods were used to create matched cohorts of rivaroxaban and apixaban patients, adjusting for demographics, risk factors for nonadherence (e.g., bipolar, anxiety), previous OAC use, and clinical characteristics. Adherence was assessed using the percentage of patients with proportion of days covered ≥0.8 at 6 months. Subgroups of patients with prior OAC use, prior OAC use and a Quan-Charlson Comorbidity index ≥2, and prior OAC use with/without nonadherence risk factors were evaluated.
Results: 14,635 NVAF subjects were included in each of 2 matched cohorts. All baseline characteristics were balanced between cohorts. At 6 months, significantly more rivaroxaban users were adherent to treatment as compared to apixaban users (82.4% vs 78.5%; absolute difference of 3.9%; P<0.01). Rivaroxaban users had significantly higher adherence rates in all subgroups examined with prior OAC agents (Figure).
Conclusion: Rivaroxaban users had consistently higher adherence rates than apixaban users overall and among all NVAF subgroups examined.