Background: There are no head-to-head randomized controlled trials comparing different direct oral anticoagulants (DOACs). Thus, we systematically reviewed and meta-analyzed observational studies assessing the comparative effectiveness and safety of DOACs for stroke prevention in patients with atrial fibrillation (AF).
Methods: We systematically searched MEDLINE and EMBASE up to February 2019 for observational studies comparing different DOACs head-to-head in patients with AF. Two independent reviewers identified studies, extracted data, and assessed the risk of bias using the Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool. Random-effects models were used to meta-analyze data across higher-quality studies.
Results: We identified 25 cohort studies including 1,079,565 patients with AF treated with DOACs. Meta-analysis of the 19 studies at moderate risk of bias yielded a similar risk of ischemic stroke for rivaroxaban versus dabigatran (six studies; hazard ratio [HR] 0.93; 95% confidence interval [CI] 0.83-1.04; I2: 0%), apixaban versus dabigatran (five studies; HR 0.94; 95% CI 0.82-1.09; I2: 0%), and apixaban versus rivaroxaban (four studies; HR 1.07; 95% CI 0.93-1.23; I2: 0%). Regarding major bleeding, there was an increased risk for rivaroxaban versus dabigatran (six studies; HR 1.33; 95% CI 1.20-1.47; I2: 22%) and decreased risks for apixaban versus either dabigatran (eight studies; HR 0.71; 95% CI 0.64-0.78; I2: 0%) or rivaroxaban (eight studies; HR 0.56; 95% CI 0.48-0.65; I2: 69%).
Conclusions: As head-to-head trials comparing different DOACs do not exist, available evidence derives exclusively from observational studies. These data suggest that while dabigatran, rivaroxaban, and apixaban have a similar effect on the risk of ischemic stroke, apixaban may be associated with a decreased risk of major bleeding compared with either dabigatran or rivaroxaban.