Net clinical benefit of anticoagulant treatments in elderly patients with nonvalvular atrial fibrillation: Experience from the real world

Background: Oral anticoagulation (OAC) is effective in stroke prevention in elderly patients with nonvalvular atrial fibrillation (AF), but older patients are also at higher risk of bleeding. Objective: We aimed to examine whether OAC has net clinical benefit (NCB) in elderly patients with AF. Methods: This is a retrospective cohort study of patients with AF, aged 75 years and older, who were diagnosed from January 1, 2013, through December 31, 2015. Incidences of stroke and intracranial hemorrhage (ICH) were estimated as the number of events per 100 person-years. The NCBs were estimated with respect to time in therapeutic range (TTR) (<60% or ≥60%) and treatment type (warfarin and low or high dose of direct oral anticoagulants [DOACs]). Results: We included 11,760 patients, of whom 4982 (42.4%) were treated with OACs: 2042 (17.4%) with warfarin and 2940 (25.0%) with DOACs. Among patients treated with warfarin, those who achieved TTR ≥ 60% had a lower incidence of stroke (2.54 per 100 person-years vs 5.21 per 100 person-years; P =.01) but without a statistically significant lower incidence of ICH (0.68 per 100 person-years vs 1.10 per 100 person-years; P =.45) and a higher NCB (9.78 vs 6.52) than did those with TTR < 60%. Among patients treated with DOACs, patients treated with the high dose had a statistically significant similar incidence of stroke (8.40 per 100 person-years vs 9.81 per 100 person-years; P =.67), a statistically significant lower incidence of ICH (0.33 per 100 person-years vs 1.20 per 100 person-years; P =.02), and a higher NCB (4.42 vs 1.78) than did patients treated with the low dose. Conclusion: A large proportion of elderly patients are not treated with OACs. We found that the NCB of OAC in the elderly is positive, with the highest benefit in elderly patients treated with warfarin who achieved TTR ≥ 60% or high dose of DOACs.