Background

Apixaban and rivaroxaban are increasingly used for thromboembolism prophylaxis in patients with nonvalvular atrial fibrillation (NVAF) and commonly in patients with obesity and body mass index (BMI) ≥50 kg/m2 despite limited data.

Objectives

This study aimed to establish the effectiveness and safety of apixaban and rivaroxaban in patients with NVAF and BMI ≥50 kg/m2.

Methods

A single health-system, retrospective cohort study evaluated the effectiveness and safety of apixaban and rivaroxaban initiated in adult patients (≥18 years of age) with BMI ≥50 kg/m2 and NVAF. Outcomes of ischemic stroke, systemic embolic events, and bleeding were compared to a cohort of patients with BMI 18 to 30 kg/m2.

Results

After 1,619 patient-years’ worth of follow up in 595 patients, the primary endpoint of incidence of ischemic stroke was numerically similar in both groups, 1.3 per 100 patient-years in the BMI ≥50 kg/m2 group, compared to 2.0 per 100 patient-years in the BMI <30 kg/m2 group (RR 0.65, 95% CI 0.38-1.82, p = 0.544). Incidence of major bleeding and clinically relevant non-major bleeding was also numerically similar between the two groups.

Conclusions

This study demonstrated that apixaban and rivaroxaban in patients with a BMI ≥50 kg/m2 for treatment of NVAF may be safe and effective at preventing thromboembolic events and had no increased risk of bleeding. Although, findings should be interpreted with caution and confirmed with additional studies. This study contributes to the growing body of evidence that direct oral anticoagulants (DOACs) may be effective and safe to use for the treatment of NVAF in patients with BMI ≥50 kg/m2.