Major Hemorrhage Risk Associated with Direct Oral Anticoagulants in Non-Valvular Atrial Fibrillation: A Systematic Review and Meta-Analysis

Background: Real-world, observational studies have investigated the safety profile of Direct Oral Anticoagulants (DOACs) on Major Hemorrhage (MH) used for stroke prevention in Non-Valvular Atrial Fibrillation (NVAF). We performed a systematic review and meta-analysis to investigate the comparative safety of DOACs versus other DOACs and versus Vitamin K Antagonists (VKAs) adhering to PRISMA guidelines. We defined MH according to the International Society on Thrombosis and Haemostasis statement or as the composite outcome of intracranial, gastrointestinal, genitourinary, respiratory, cavitary and musculoskeletal bleeding in case of studies using International Statistical Classification of Diseases codes for patient selection.

Methods: We systematically investigated two databases (Medline, Embase) until April of 2021, gathered observational studies and extracted hazard ratios (HRs) with 95% confidence intervals (CI) on our outcome of interest. Additional subgroup analyses according to DOAC dosing, prior diagnosis of chronic kidney disease, prior diagnosis of stroke, history of previous use of VKA, the users' age, the users' gender and study population geographic region were conducted. All analyses were performed with a random-effects model.

Results: From this search, 55 studies were included and 76 comparisons were performed. The MH risk associated with Rivaroxaban use was higher than the risk with Dabigatran use (HR: 1.32, 95% CI: 1.21-1.45, $I^2$ : 12.39%) but similar to VKA use (HR: 0.94, 95% CI: 0.87-1.02, $I^2$ : 76.57%). The MH risk associated with Dabigatran use was lower than the risk with VKA use (HR: 0.75, 95% CI: 0.64-0.90, $I^2$ : 87.57%). The MH risk associated with Apixaban use was lower than the risk with Dabigatran use (HR: 0.75, 95% CI: 0.64-0.88, $I^2$ : 58.66%), with Rivaroxaban use (HR: 0.58, 95% CI: 0.50-0.68, $I^2$ : 74.16%) and with VKA use (HR: 0.60, 95% CI: 0.55-0.65, $I^2$ : 58.83%). Our aforementioned subgroup analyses revealed similar results.

Conclusions: All in all, Apixaban was associated with a reduced MH risk compared to Dabigatran, Rivaroxaban and VKA. Dabigatran was associated with a reduced MH risk compared to both Rivaroxaban and VKA.