Group-based trajectory modeling to identify adherence patterns for direct oral anticoagulants in Medicare beneficiaries with atrial fibrillation: a real-world study on medication adherence.

Background: Suboptimal adherence to direct oral anticoagulants (DOACs) among atrial fibrillation (AF) patients remains currently a major concern due to the increased risk of cardiac and thromboembolic events.

Aim: To identify longitudinal distinct trajectories of DOAC adherence and sociodemographic and clinical factors associated with each trajectory.

Method: Patients with AF who were prescribed with DOAC from July 2016-December 2017 were identified among patients enrolled in the Medicare Advantage Plan. Patients were followed up for a year after the index date to calculate the monthly proportion of days covered (PDC). The monthly PDC was incorporated into the logistic group-based trajectory model to evaluate distinct patterns of adherence. A multinomial regression model was carried out to assess various predictors associated with each trajectory. Sub-group analysis was conducted among incident DOAC users.

Results: Total of 1969 patients with AF, four distinct trajectories of adherence were selected: adherent 36.8%, gaps in adherence 9.3%, gradual decline in adherence 29.7%, and rapid decline in adherence 24.2%. Significant predictors associated with suboptimal adherence trajectories were age (75 years or older), gender (male vs female), low-income subsidy health plan, prevalent users, and presence of comorbidities. Among 933 incident users, three adherence trajectories were identified: adherent trajectory (31.8%), rapid decline in adherence (32.5%), and gradual decline in adherence (35.6%). The significant predictors among incident users were gender (male vs female), low-income subsidy health plan, HAS-BLED score ≥ 2, and presence of coronary artery disease.

Conclusion: Adherence to DOACs was suboptimal among the total population and incident users.