Medication Adherence and Antithrombotic Therapy Outcomes

BACKGROUND: The AFIRE (Atrial Fibrillation and Ischemic Events With Rivaroxaban in Patients With Stable Coronary Artery Disease) trial demonstrated that rivaroxaban monotherapy has noninferior efficacy and superior safety compared with combination therapy (rivaroxaban plus a single antiplatelet) in patients with atrial fibrillation and stable coronary artery disease. OBJECTIVES: This post hoc analysis aimed to explore the impact of medication adherence on the AFIRE trial results. METHODS: A total of 2,120 patients were categorized into adherent and nonadherent groups based on self-reported assessments, which were further validated through on-site visits to the facilities. Adherence was defined as continuous medication use as prescribed. The primary efficacy endpoint was a composite of stroke, systemic embolism, myocardial infarction, revascularization requiring unstable angina, or all-cause death. The primary safety endpoint was major bleeding events. RESULTS: Among the 2,012 (94.9%) adherent patients, rivaroxaban monotherapy showed significantly better outcomes compared with combination therapy regarding both efficacy (HR: 0.72; 95% CI: 0.53-0.96; P = 0.028) and safety (HR: 0.63; 95% CI: 0.41-0.97; P = 0.034). However, no significant differences in outcomes were shown in nonadherent patients (n = 108). There was no interaction between medication adherence and the randomized treatment group. In clinically high-risk patients with a history of angina pectoris, compared with nonadherent patients (n = 68), those who demonstrated medication adherence (n = 1,281) exhibited significantly better efficacy outcomes (HR: 0.52; 95% CI: 0.30-0.97; P = 0.041). CONCLUSIONS: High adherence to rivaroxaban monotherapy was associated with improved outcomes, underscoring the importance of adherence in achieving optimal therapeutic effects (Atrial Fibrillation and Ischemic Events With Rivaroxaban in Patients With Stable Coronary Artery Disease [AFIRE], NCT02642419; AFIRE Study: Atrial Fibrillation and Ischemic events with Rivaroxaban in patiEnts with stable coronary artery disease Study, UMIN000016612).