Real‐World Comparative Effectiveness and Safety of Non‐Vitamin K Antagonist Oral Anticoagulants vs. Warfarin in a Developing Country

We aimed to compare effectiveness and safety of the non-vitamin K antagonist oral anticoagulants (NOACs) vs. warfarin for stroke prevention in nonvalvular atrial fibrillation (NVAF) in a developing country where anticoagulation control with warfarin is suboptimal. A real-world study was conducted among patients with NVAF in Thailand receiving NOACs and warfarin from 9 hospitals during January 2012 to April 2018. Propensity-score weighting was used to balance covariates across study groups. Cox regression models were used to compare the risk of thromboembolism, major bleeding, and net adverse clinical events across matched cohorts. A total of 2,055 patients; 605, 604, 441, and 405 patients receiving warfarin, rivaroxaban, dabigatran, and apixaban, respectively, were included. Median (interquartile range) time in therapeutic range (TTR) for warfarin users was 49.5% (26.6%-70.3%). Compared with warfarin, NOACs were associated with a significant reduction in major bleeding either when analyzed as a group (adjusted hazard ratio (HR) (95% confidence interval (CI)) of 0.46 (0.34-0.62) or by each agent. Compared with warfarin users with poor TTR, apixaban (adjusted HR 0.48, 95% CI 0.26-0.86, P = 0.013) and dabigatran (adjusted HR 0.44, 95% CI 0.21-0.90, P = 0.025) were associated with a lower risk of thromboembolism, in addition to markedly lower risk of major bleeding. In a healthcare system where anticoagulation control with warfarin is suboptimal, use of NOACs was associated with a profound reduction in major bleeding. The effectiveness and safety advantages of NOACs were more pronounced compared with warfarin users with low TTR.