Net Clinical Benefit of Oral Anticoagulation Among Older Adults With Atrial Fibrillation

Abstract

Background: While guidelines recommend anticoagulation for all atrial fibrillation (AF) patients ≥75 years, evidence for the net clinical benefit (NCB) of anticoagulant in older adults is sparse. We sought to determine the association between age and NCB of anticoagulation in older adults with AF. Methods and Results: We examined adults ≥75 years with incident AF in the Anticoagulation and Risk Factors in Atrial Fibrillation—Cardiovascular Research Network cohort. Using a Markov state transition model, we estimated the lifetime NCB of warfarin and apixaban relative to no treatment in quality-adjusted life years (QALYs). In the decision model, each month patients face a chance of stroke, hemorrhage, or death from a competing cause; the likelihood of each is a function of individual patients’ stroke risk, hemorrhage risk, and life expectancy. We defined minimal clinically relevant lifetime benefit as 0.10 QALYs. In a sensitivity analysis, we examined the effect of competing risks of death on NCB using 2 models, one including competing risks and the second without competing risks. We included 14 946 patients, with a median age of 81 years and median CHA 2 DS 2 -VASc score of 4. In the main analysis, after age 87, NCB associated with warfarin decreased below 0.10 lifetime QALYs while NCB associated with apixaban did not decrease below 0.10 lifetime QALYs until after age 92. In sensitivity analyses, over a 3-year horizon, removing competing risks of death resulted in higher NCB (at 90 years, median difference using warfarin 0.010 QALYs [95% CI, 0.009–0.013], median difference using apixaban 0.025 QALYs [95% CI, 0.024–0.026]). Conclusions: The NCB of anticoagulation decreases with advancing age. The competing risk of death diminishes the NCB of anticoagulation for older patients with AF. Physicians should consider competing mortality risks when recommending anticoagulants to older adults with AF.