To treat or not to treat: a comparative effectiveness analysis of oral anticoagulant outcomes among U.S. nursing home residents with atrial fibrillation.

ABSTRACT

BACKGROUND: Nursing home residents with atrial fibrillation are at high risk for ischemic stroke, but most are not treated with anticoagulants. This study compared the effectiveness and safety between oral anticoagulant (OAC) users and non-users. METHODS: We conducted a new-user retrospective cohort study by using Minimum Data Set 3.0 assessments linked with Medicare claims. The participants were Medicare fee-for-service beneficiaries with atrial fibrillation residing in US nursing homes between 2011 and 2016, aged ≥ 65 years. The primary outcomes were occurrence of an ischemic stroke or systemic embolism (effectiveness), occurrence of intracranial or extracranial bleeding (safety) and net clinical outcome (effectiveness or safety outcomes). Secondary outcomes included total mortality and a net clinical and mortality outcome. Cox proportional hazards and Fine and Grey models estimated multivariable adjusted hazard ratios (aHRs) and sub-distribution hazard ratios (sHRs). RESULTS: Outcome rates were low (effectiveness OAC 0.86; non-users 1.73; safety OAC 2.26; non-users 1.75 (per 100 person-years)). OAC use was associated with a lower rate of the effectiveness outcome (sHR 0.69; 95% Confidence Interval (CI) 0.61-0.77), higher rates of the safety (sHR 1.70; 95% CI 1.58-1.84) and net clinical outcomes (sHR 1.20; 95% CI 1.13-1.28) lower rate of all-cause mortality outcome (sHR 0.60; 95% CI 0.59-0.61), and lower rate of the net clinical and mortality outcome (sHR 0.60; 95% CI 0.59-0.61). Warfarin users, but not DOAC users, had a higher rate of the net clinical outcome versus OAC non-users. CONCLUSIONS: Our results support the benefits of treatment with OACs to prevent ischemic strokes and increase longevity, while highlighting the need to weigh apparent benefits against elevated risk for bleeding. Results were consistent with net favorability of DOACs versus warfarin.