Use of Warfarin in Elderly Patients With Non-Valvular Atrial Fibrillation　– Subanalysis of the J-RHYTHM Registry –

BACKGROUND: To clarify the effects of warfarin therapy in very old patients with non-valvular atrial fibrillation (NVAF), a post-hoc analysis was performed using the data of the J-RHYTHM Registry. METHODS AND RESULTS: A consecutive series of AF outpatients was enrolled from 158 institutions. Of 7,937 patients, 7,406 with NVAF (men, 70.8%; 69.8±10.0 years) were followed for 2 years or until an event occurred. Patients were divided into 3 age groups (<70, 70-84, and ≥85 years) and 5 subgroups according to international normalized ratio (INR; <1.6, 1.6-1.99, 2.0-2.59, 2.6-2.99, and ≥3.0). Prevalence of female sex, permanent AF, hypertension, coronary artery disease, heart failure, and history of ischemic stroke/transient ischemic attack was higher in the older groups. In the oldest group, 79.7% of patients received warfarin and their time in therapeutic range, using the Japanese target INR of 1.6-2.6, was 67.1%. Rate of thromboembolic events was lower in the age groups <70 and 70-84 years (P=0.027 and P<0.001, respectively) for patients receiving warfarin compared with those who were not. In the oldest group, the rate of thromboembolism plus major hemorrhage was lower at INR 1.6-2.59. CONCLUSIONS: Warfarin could have beneficial effects even in very old NVAF patients if INR is kept between 1.6 and 2.59.