BackgroundThe safety and efficacy of an oral anticoagulant (OAC) treatment and the difference between direct OACs (DOACs) and warfarin in nonsevere frail elderly patients with AF are unclear.MethodsThis was a retrospective and observational study of 354 patients over 80 years of age with nonsevere frailty who were diagnosed with AF and treated with OACs. Nonsevere frailty was defined as a clinical frailty scale score of <7. Bleeding and thromboembolic events during the OAC treatment were followed up.ResultsOf 354 patients enrolled, 273 (77.1%) received DOACs and 81 (22.9%) received warfarin. Of 273 patients receiving DOACs, there were 210 (76.9%) prescribed with appropriate doses of DOACs. Of 81 warfarin‐treated patients, 53 (65.4%) were prescribed an appropriate dose of warfarin. During a follow‐up of 33.1 (14.0‐51.0) months, 15 patients (1.5/100 person‐years) had bleeding events and 10 (1.0/100 person‐years) had thromboembolic events while on an OAC treatment. The incidence ratio of bleeding events in patients receiving DOACs was lower than that in those receiving warfarin (1.0/100 person‐years vs 2.9/100 person‐years, hazard ratio [HR]: 0.26, 95% confidence interval [CI]: 0.07‐0.91, P = .036). There was no significant difference in the incidence of thromboembolic events between the DOAC and warfarin treatment groups (0.88/100 person‐years vs 1.4/100 person‐years, HR: 0.63, 95% CI: 0.16‐2.57, P = .52).ConclusionsOACs are substantially safe and effective for preventing thromboembolic events in nonsevere frail patients over 80 years of age. Particularly, DOACs can be used more safely than warfarin.