Oral Anticoagulants in Very Elderly Nonvalvular Atrial Fibrillation Patients With High Bleeding Risks: ANAFIE Registry

Background: Data on the effectiveness and safety of oral anticoagulant (OAC) agents in very elderly nonvalvular atrial fibrillation patients with high bleeding risk are lacking. Objectives: This study examined 2-year outcomes and effects of OAC agents among these patients using the ANAFIE (All Nippon Atrial Fibrillation in the Elderly) registry (N = 32,275) data. Methods: Patients were classified into high-risk (age: ≥80 years; CHADS₂ score: ≥2; and presence of ≥1 bleeding risk factor: creatinine clearance of 15-30 mL/minute, prior bleeding at critical sites, body weight of ≤45 kg, or continuous antiplatelet use) and reference groups. Results: In the high-risk (n = 7,104) and reference (n = 25,171) group patients, 89.0% and 93.4%, respectively, used OAC agents. Of these, respectively, 30.1% and 24.2% used warfarin, and 58.9% and 69.1% used direct-acting OAC (DOAC) agents. Compared with the reference group, the high-risk group had higher incidences of stroke/systemic embolism, major bleeding, intracranial hemorrhage, gastrointestinal bleeding, cardiovascular events, and all-cause death. In the high-risk group, DOAC agent use vs nonuse of OAC agents was associated with reduced incidences of stroke/systemic embolism (HR: 0.53; 95% CI: 0.36-0.79) and all-cause death (HR: 0.65; 95% CI: 0.52-0.81) but not with major bleeding (HR: 1.09; 95% CI: 0.63-1.89). DOAC agents were superior to warfarin in effectiveness and safety. For high-risk patients, history of major bleeding, severe liver dysfunction, and falls within 1 year were independent risk factors for major bleeding. Conclusions: High-risk elderly nonvalvular atrial fibrillation patients had higher event incidences. DOAC agents were associated with reduced risk of stroke/systemic embolism and all-cause death vs nonuse of OAC agents or warfarin.