Antithrombotic treatment switching in elderly patients with atrial fibrillation and the risk of thromboembolism, bleeding, and cardiac death.

Background: Risks of antithrombotic switching is not investigated in elderly atrial fibrillation patients.

Objectives: To investigate the effectiveness and safety of antithrombotic treatment and switching of antithrombotic treatment in elderly patients (aged 75 years or older) with atrial fibrillation (AF).

Methods: We conducted a cohort study of 2943 patients with AF (Carrebean-elderly), hospitalized during 2010-2017. Cox models were used to estimate the association of antithrombotic treatment (warfarin, direct oral anticoagulants [DOAC] and non-guideline-recommended therapy [NG], i.e., aspirin and low-molecular-weight heparin) at discharge and antithrombotic treatment switching during follow-up with the risk of a composite and single end points of thromboembolism, bleeding, and cardiac death. Crude and adjusted risk estimates were expressed as hazard ratios (HRs) with 95% confidence intervals (CIs). All-cause death was evaluated, with competing risk regression and estimates expressed as subhazard ratios and 95% CIs.

Results: We observed an increased risk for the composite end point associated with NG as compared to warfarin at discharge (HR, 1.18; 95% CI, 1.01-1.38) with congruent competing risk regression results, while no significant risk difference was seen for DOACs compared to warfarin (HR, 1.12; 95% CI, 0.92-1.36). Switching from NG to warfarin/DOAC and from warfarin to DOAC occurred in 30.4% and 33.1% of respective antithrombotic treatment groups at discharge and was associated with a decreased risk for the composite end point with an adjusted HR of 0.45 (95% CI, 0.32-0.63) and a HR of 0.50 (95% CI, 0.38-0.65), respectively.

Conclusions: Antithrombotic treatment switching is common in the elderly AF population. Importantly, switching to guideline-recommended treatment has a favorable impact on both effectiveness and safety.