Efficacy and Harms of Direct Oral Anticoagulants in the Elderly for Stroke Prevention in Atrial Fibrillation and Secondary Prevention of Venous Thromboembolism

Abstract

Background-Evidence regarding use of direct oral anticoagulants (DOACs) in the elderly, particularly bleeding risks, is unclear despite the presence of greater comorbidities, polypharmacy and altered pharmacokinetics in this age group. Methods and Results-We performed a systematic review and meta-analysis of randomised trials of DOACs (dabigatran, apixaban, rivaroxaban, edoxaban) for efficacy and bleeding outcomes compared to VKA (vitamin k antagonists) in elderly participants (aged ≥75 years) treated for acute venous thromboembolism or stroke prevention in atrial fibrillation. Nineteen studies were eligible for inclusion but only 11 reported data specifically for elderly participants. Efficacy in managing thrombotic risks for each DOAC was similar or superior to VKA in the elderly. A non-significantly, higher risk of major bleeding than VKA was observed with dabigatran 150mg (Odds Ratio 1.18, 95% confidence interval 0.97-1.44) but not with the 110mg dose. Significantly higher gastrointestinal bleeding risks with dabigatran 150mg (1.78, 1.35-2.35) and 110mg (1.40, 1.04-1.90) and lower intracranial bleeding risks than VKA for dabigatran 150mg (0.43, 0.26-0.72) and dabigatran 110mg (0.36, 0.22-0.61) were also observed. A significantly lower major bleeding risk compared to VKA was observed for apixaban (0.63, 0.51-0.77), edoxaban 60mg (0.81, 0.67-0.98) and 30mg (0.46, 0.38-0.57) while rivaroxaban showed similar risk. Conclusion-DOACs demonstrated at least equal efficacy to VKA in managing thrombotic risks in the elderly however bleeding patterns were distinct. In particular, dabigatran was associated with a higher risk of gastrointestinal bleeding than VKA. Insufficient published data for apixaban, edoxaban and rivaroxaban indicates further work is needed to clarify their bleeding risks in the elderly