OBJECTIVES: Suboptimal adherence to oral anticoagulants (OACs) to treat atrial fibrillation (AF) can lead to poor treatment outcomes. This study aimed to evaluate variations in adherence and persistence to OACs among AF patients across stroke risk (CHA2DS2-VASc) and bleeding risk (HAS-BLED2) strata.

METHODS: This retrospective cohort analysis used national claims database, Optum, to assess adherence and persistence in the first year for patients initiating an OAC for a primary diagnosis of AF between 10/2016-04/2021. Eligible patients were ≥45 years with continuous health plan enrollment for 12 months prior to and after their first captured OAC claim (index). Persistence was measured as the time between the index date and a 30+ day gap in coverage or medication switching. Adherence was measured by proportion of days covered (PDC) from therapy initiation to medication discontinuation, switching, or end of follow-up.

RESULTS: Of 150,482 patients identified, the majority initiated with apixaban, rivaroxaban, and warfarin (66.9%, 20.4%, and 10.9% respectively). Average overall persistence in the year after initiation was 228.3 days (SD 138.8). Over 50% of patients were persistent at 6 months in all risk groups excepting low stroke and low bleed risk (37% for apixaban and rivaroxaban, 43% for warfarin). Persistence was highest for high stroke, low bleeding risk patients across all drugs. On average, 75.2% of the total population was adherent at least 80% of days covered with no significant difference between drugs (p=0.662). Adherence to apixaban and rivaroxaban decreased with increasing bleeding risk. The highest percent of patients with PDC≥80% was 80% of patients using DOACs in low to medium stroke risk, regardless of bleed risk.

CONCLUSIONS: Adherence and persistence rates vary across stroke risk by drug, but generally decrease with increased bleeding risk within stroke risk groups. Newer therapies with lower bleeding risk are needed.