Background: The combination of oral anticoagulant (OAC) and antiplatelet drug (APD) increases the bleeding risk in atrial fibrillation (AF). Non-vitamin K antagonist OAC (NOAC) have been increasingly used since 2011. We investigated current status, time trends and outcomes of AF patients using combination therapy in 2011–2017.
Methods and Results: The Fushimi AF Registry is a community-based prospective survey of AF patients in Fushimi-ku, Kyoto, Japan. Of 2,378 patients with OAC at enrollment, 521 (22%) received combination therapy, while 1,857 (78%) received OAC alone. When compared with OAC alone, combination therapy patients had more comorbidities, but approximately 30% had no atherosclerotic disease. From 2011 to 2017, the prevalence of combination therapy decreased from 26% to 14%. The prevalence of NOAC increased in those on combination therapy. Off-label under-dosing of NOAC increased year by year, especially in combination therapy. During follow-up, the incidence of major bleeding (hazard ratio [HR], 1.42; 95% CI: 1.03–1.95) and stroke/systemic embolism (HR, 1.48; 95% CI: 1.09–2.00) was higher in the combination therapy than in the OAC alone group.
Conclusions: In Japanese AF patients receiving OAC, the prevalence of combination therapy decreased, with the proportion of NOAC use increasing in 2011–2017. Many patients, however, received off-label NOAC under-dosing, especially in the combination therapy group. Patients with combination therapy had higher incidences of major bleeding as well as stroke/systemic embolism, compared with OAC monotherapy.