Background: Chronic anticoagulation with warfarin is recommended in patients with hypertrophic cardiomyopathy (HCM) and atrial fibrillation (AF). Non-vitamin K oral anticoagulants (NOACs) are an alternative to warfarin but there are limited data to support their use in HCM.
Purpose: We sought to describe the pattern of use, stroke events, bleeding and mortality in patients with HCM and AF treated with NOACs, in comparison to those treated with warfarin.
Methods: Using the Korean National Health Insurance Service (NHIS) data during the period from 2011 to 2016, we identified patients with HCM and AF treated with NOACs (n=2302) and warfarin (n=1188). Comparisons on efficacy and safety outcomes were made on the basis of Cox-proportional hazards models stratified on 1:1 propensity score (PS)-matched NOAC (n=946) and warfarin groups (n=946).
Results: Baseline characteristics were well balanced between the two matched groups. Median age was 67 years (interquartile range: 58 to 74 years), 55.9% male, and median CHA2DS2-VASc score was 5 (interquartile range: 3 to 6). A total of 51.9% of the NOAC-treated patients received a reduced dose of dabigatran, rivaroxaban, or apixaban. After a mean 1.30 years of follow-up, the incidence of ischemic stroke and major bleeding were similar between NOAC- and warfarin treated patients. The incidence for ischemic stroke was 10.99 and 9.38 per 100 person-years for NOACs and warfarin, respectively (adjusted hazard ratio [aHR]: 0.996; 95% confidence interval [CI] 0.763–1.299; p=0.975). Major bleeding occurred in 5.48 per 100 person-years in the NOAC group vs. 5.26 in warfarin group (aHR: 0.932; 95% CI 0.649–1.338; p=0.703). However, patients treated with NOAC showed a significantly lower risk of all-cause mortality and the composite net clinical outcome (ischemic stroke, major bleeding, and all-cause death) compared to those on warfarin. The incidence of all-cause death was 4.98 and 10.69 per 100 person-years for NOACs and warfarin, respectively (aHR: 0.442; 95% CI 0.318–0.613; p<0.0001). The benefits were consistent across various high-risk subgroups.
Conclusions: Compared with those with warfarin, HCM patients with AF on NOACs had lower risk of all-cause mortality and similar risk of major bleeding and ischemic stroke.