Meta-Analysis of Efficacy and Safety of Low-Intensity Warfarin Therapy for East Asian Patients With Nonvalvular Atrial Fibrillation

For patients with nonvalvular atrial fibrillation (NVAF) receiving warfarin therapy, the target international normalized ratio range of 2.0 to 3.0 is recommended by Western countries. However, this treatment carries a higher risk of bleeding which suggests more researches on whether low-intensity warfarin therapy (range <2.0 to 3.0) is suitable for East Asian patients. Three databases were searched from inception to April 21, 2016. Studies that reported thromboembolic and hemorrhagic events in low- and standard-intensity warfarin groups were included. Finally, seven studies were included in the analysis. There was a significantly decreased risk of hemorrhagic events (odds ratio [OR] 0.59, 95% confidence interval [CI] 0.43 to 0.82, p = 0.002) with no statistically increased risk of thromboembolic events (OR 1.14, 95% CI 0.80 to 1.62, p = 0.47) in the 1.5 to 2.0 group compared with that of the 2.0 to 3.0 group. Meanwhile, there was no significant difference of cardiovascular mortality (OR 1.58, 95% CI 0.89 to 2.83, p = 0.12) between the 2 groups. Further analysis showed there was no significance in thromboembolic events (OR 1.15, 95% CI 0.83 to 1.60, p = 0.40), major bleeding events (OR 0.74, 95% CI 0.50 to 1.09, p = 0.13), and cardiovascular mortality (OR 1.45, 95% CI 0.79 to 2.65, p = 0.23) between 1.5 to 2.5 and 2.0 to 3.0 groups. Although no significant difference was found in hemorrhagic events (OR 0.76, 95% CI 0.57 to 1.01, p = 0.06), there was a decreased trend in it. In conclusion, low-intensity warfarin therapy can achieve reduced hemorrhage without increasing thromboembolism for East Asian patients with NVAF receiving warfarin therapy.