Effectiveness of Novel Oral Anticoagulants Versus Warfarin in Patients With Atrial Fibrillation: A Systematic Review and Meta-Analysis.

Atrial fibrillation (AF) is a common cardiac arrhythmia associated with an increased risk of stroke and systemic embolism (SE). Anticoagulation therapy, particularly with vitamin K antagonists (VKA) or novel oral anticoagulants (NOACs), is essential for stroke prevention in patients with AF. However, the comparative effectiveness of NOACs and warfarin remains debatable. Of the 34 studies included, 14 studies involving 166,845 patients were included in the meta-analysis and 20 studies were included in the systematic review. Our findings indicate that NOACs were associated with a significantly lesser risk of stroke/SE with a relative risk (RR) of 0.84 and p=0.0005, and all-cause mortality RR=0.88 and p=0.006. There were no significant differences between major bleeding events with an RR of 0.87 and p=0.22, and serious adverse events (SAE) with RR=1.01 and p=0.35, compared to warfarin in patients with AF. Our meta-analysis demonstrates strong evidence for the superiority in reducing stroke/SE and all-cause mortality of NOACs compared to warfarin. However, no significant differences were identified in the bleeding outcomes or SAEs between the two groups.