Efficacy and Safety of Non–Vitamin K Antagonist Oral Anticoagulants in Atrial Fibrillation Patients With Impaired Liver Function: A Retrospective Cohort Study

BACKGROUND: Patients with impaired liver function (ILF) were excluded from clinical trials that investigated non–vitamin K antagonist oral anticoagulants (NOACs) for stroke prevention in patients with atrial fibrillation. The aim of this study was to evaluate the efficacy and safety of NOACs in atrial fibrillation patients with ILF. METHODS AND RESULTS: A cohort study based on electronic medical records was conducted from 2009 to 2016 at a multicenter healthcare provider in Taiwan and included 6451 anticoagulated atrial fibrillation patients (aged 76.7±7.0 years, 52.5% male). Patients were classified into 2 subgroups: patients with normal liver function (n=5818) and patients with ILF (n=633, 9.8%). Cox regression analysis was performed to investigate the risks of thromboembolism, bleeding, and death associated with use of NOACs and warfarin in patients with normal liver function and ILF, respectively. In patients with normal liver function, compared with warfarin therapy (n=2928), NOAC therapy (n=4048) was associated with significantly lower risks of stroke or systemic embolism (adjusted hazard ratio: 0.75; 95% confidence interval, 0.65–0.88; P<0.001) and death (adjusted hazard ratio: 0.69; 95% confidence interval, 0.60–0.80; P<0.001) with no difference in major bleeding or gastrointestinal bleeding. In patients with ILF, compared with warfarin therapy (n=394), NOAC therapy (n=342) was associated with significantly lower risk of death (adjusted hazard ratio: 0.64; 95% confidence interval, 0.49–0.83; P<0.001), but no difference in stroke or systemic embolism, major bleeding, or gastrointestinal bleeding. CONCLUSIONS: In atrial fibrillation patients with ILF, NOAC therapy and warfarin therapy were associated with similar risks of stroke or systemic embolism, major bleeding, and gastrointestinal bleeding.