Bleeding rates of Veterans taking apixaban or rivaroxaban for atrial fibrillation or venous thromboembolism.

This study examined potential differences in bleeding between apixaban and rivaroxaban, the most commonly utilized direct oral anticoagulants at the Richard L. Roudebush VA Medical Center. Additionally, the analysis included a comparison between observed and literature-reported bleeding rates. This retrospective chart review examined 452 (39%) Veterans receiving rivaroxaban and 716 (61%) Veterans receiving apixaban. Bleeding rates were expressed per 100 patient-years and the overall rates were analyzed as the primary analysis. Secondary objectives included comparisons based on indication and severity, as well as comparisons to literature-reported bleed rates, time to bleeding event, and location of the bleed. The analysis did not detect any statistically significant differences between apixaban and rivaroxaban in terms of overall, (ARR 0.90% per 100 patient-years, 95% CI - 0.58 to 2.38%, p > 0.05) major, (ARR 0.22% per 100 patient-years, 95% CI - 0.74 to 1.17%, p > 0.05) or non-major clinically relevant (ARR 0.35% per 100 patient-years, 95% CI - 0.57 to 1.27%, p > 0.05) bleeding. Observed bleeding for both rivaroxaban and apixaban in the Veteran population exceeded the rates reported by the literature when used for atrial fibrillation (1.96% vs. 0.15%, p < 0.05; 1.08% vs. 0.16%, p < 0.05) but the opposite was seen for long term venous thromboembolism (VTE) treatment (3.97% vs. 8.03%, p < 0.0001; 0.14% vs. 15.51%, p < 0.0001) or extended VTE prophylaxis (0.07% vs 5.98%, p < 0.0001; 0.07% vs 1.88%, p < 0.01). Results from this study suggest these agents impart similar levels of risk, but variations in bleeding risk between the Veteran population and the patients in the original clinical trials may exist.