Background: Warfarin is commonly used as a secondary prevention of stroke in patients with atrial fibrillation (AF). However, limitations have been observed even with the use of this medication. Recently, several newer direct oral anticoagulants (DOACs) have been approved for use by the food and drug administrations. Unfortunately, these newer drugs have seldom been compared directly with each other. Therefore, this study aimed to compare the bleeding events associated with rivaroxaban and dabigatran in patients treated for non-valvular AF.
Methods: EMBASE, Medline (National Library of Medicine) and the Cochrane Central Registry of Controlled Trials were searched for studies comparing rivaroxaban with dabigatran using the terms 'rivaroxaban, dabigatran and atrial fibrillation'. Primary endpoints were: any bleeding outcomes, intracranial bleeding and gastro-intestinal (GI) bleeding. Secondary outcomes included stroke/systemic embolism (SE)/transient ischemic attack (TIA), venous thromboembolism and mortality. Odds ratios (OR) with 95% confidence intervals (CIs) were calculated. The pooled analyses were carried out with RevMan 5.3 software. All the authors had full access to the data and approved the manuscript as written.
Results: A total number of 4895 patients were included. This analysis showed that rivaroxaban was not associated with a significantly higher bleeding event when compared to dabigatran (OR: 1.28, 95% CI: 0.95-1.72; P = 0.11). GI bleeding was similarly manifested between these two DOACs (OR: 0.98, 95% CI: 0.43-2.25; P = 0.97). Even if intracranial bleeding was higher with the use of rivaroxaban, (OR: 2.18, 95% CI: 0.51-9.25; P = 0.29), the result was not statistically significant. Moreover, stroke/SE/TIA and venous thromboembolism were also not significantly different (OR: 0.81, 95% CI: 0.53-1.23; P = 0.32) and (OR: 2.06, 95% CI: 0.73-5.82; P = 0.17) respectively. However, even if mortality favored dabigatran (OR: 1.42, 95% CI: 0.99-2.06; P = 0.06), this result only approached statistical significance.
Conclusion: Head to head comparison showed that rivaroxaban was not associated with significantly higher bleeding events compared to dabigatran. Intracranial bleeding, GI bleeding, stroke/SE/TIA, venous thromboembolism and mortality were also not significantly different between these two DOACs. However, due to the limited number of patients analyzed, and which were mainly obtained from observational studies, this hypothesis might only be confirmed in future randomized trials. Furthermore, the CHADS2-VASC and HAS-BLED score which might play an important role in predicting bleeding risks should also not be ignored.
Keywords: Atrial fibrillation; Bleeding events; Dabigatran; Gastrointestinal bleeding; Intracranial bleeding; Oral anticoagulants; Rivaroxaban.