Oral anticoagulation among frail patients with atrial fibrillation: assessment of net clinical benefit in a nationwide cohort

Abstract Background Frail patients with atrial fibrillation (AF) are often undertreated with oral anticoagulants (OAC), and evidence for the net clinical benefit of OAC is sparse. Objectives We examined the risk of thromboembolic events and major bleeding, and the association between age, frailty level, and net clinical benefit (NCB) of anticoagulation. Methods This was an observational cohort study based on Danish nationwide data. Frail patients aged ≥50 years with a Hospital Frailty Risk Score ≥5 and incident AF were identified from 2013-2018. Patients were categorized according to OAC therapy, and differences in thromboembolic events and major bleeding were studied after 1 year. The NCB of anticoagulation was assessed by the bivariate trade-off between thromboembolism and bleeding. Results We identified 36223 frail AF patients (median age 79 years, 50.5% female), of whom 61.8% started OAC therapy, while 38.2% were untreated despite indication for stroke prevention. At one year, the risk of thromboembolic events was 2.1% (95% CI 1.8 to 2.3%) among patients not receiving OAC versus 1.5% (95% CI 1.4 to 1.7%) in patients with OAC. The one-year bleeding risk was 3.2% (95% CI 2.9 to 3.5%) among patients without OAC and 3.5% (95% CI 3.2 to 3.8%) among anticoagulated patients. The NCB was 0.66% (95% CI 0.19% to 1.12%) suggesting a statistically significant benefit of OAC treatment. Conclusion Frail AF patients are often untreated with OAC in routine clinical care despite an indication for stroke prevention. The NCB when balancing thromboembolic events and major bleeding was in favor of anticoagulation but decreased with advancing age and increasing frailty.