Real-World Setting Comparison of Nonvitamin-K Antagonist Oral Anticoagulants Versus Vitamin-K Antagonists for Stroke Prevention in Atrial Fibrillation: A Systematic Review and Meta-Analysis

Background and purpose: Evidence from the real-world setting complements evidence coming from randomized controlled trials. We aimed to summarize all available evidence from high-quality real-world observational studies about efficacy and safety of nonvitamin-K oral anticoagulants compared with vitamin-K antagonists in patients with atrial fibrillation.

Methods: We searched PubMed and Web of Science until January 7, 2017 for observational nationwide or health insurance databases reporting matched or adjusted results comparing nonvitamin-K oral anticoagulants versus vitamin-K antagonists in patients with atrial fibrillation. Outcomes assessed included ischemic stroke, ischemic stroke or systemic embolism, any stroke or systemic embolism, myocardial infarction, intracranial hemorrhage, major hemorrhage, gastrointestinal hemorrhage, and death.

Results: In 28 included studies of dabigatran, rivaroxaban, and apixaban compared with vitamin-K antagonists, all 3 nonvitamin-K oral anticoagulants were associated with a large reduction of intracranial hemorrhage (apixaban hazard ratio [HR], 0.45; 95% confidence interval [CI], 0.31-0.63; dabigatran HR, 0.42; 95% CI, 0.37-0.49; rivaroxaban HR, 0.64; 95% CI, 0.47-0.86); similar rates of ischemic stroke and ischemic stroke or systemic embolism (apixaban HR, 1.05; 95% CI, 0.75-1.19 and HR, 1.08; 95% CI, 0.95-1.22 / dabigatran HR, 0.96; 95% CI, 0.80-1.16 and HR, 1.17; 95% CI, 0.92-1.50 / rivaroxaban HR, 0.89; 95% CI, 0.76-1.04 and HR, 0.73; 95% CI, 0.52-1.04, respectively); apixaban and dabigatran with lower mortality (HR, 0.65; 95% CI, 0.56-0.75 and HR, 0.63; 95% CI, 0.53-0.75, respectively); apixaban with fewer gastrointestinal (HR, 0.63; 95% CI, 0.42-0.95) and major hemorrhages (HR, 0.55; 95% CI, 0.48-0.63); dabigatran and rivaroxaban with more gastrointestinal hemorrhages (HR, 1.20; 95% CI, 1.06-1.36 and HR, 1.24; 95% CI, 1.08-1.41, respectively); dabigatran and rivaroxaban with similar rate of myocardial infarction (HR, 0.96; 95% CI, 0.77-1.21 and HR, 1.02; 95% CI, 0.54-1.89, respectively).

Conclusions: This meta-analysis confirms the main findings of the randomized controlled trials of dabigatran, rivaroxaban, and apixaban in the real-world setting and, hence, strengthens their validity.