DOACs heighten stroke, reduce MI risks in patients with AF-MS

Use of direct oral anticoagulants (DOACs) vs warfarin appears to increase the 1-year risk for stroke but lower the risk for myocardial infarction (MI) in Asian patients with atrial fibrillation (AF) and mitral stenosis (MS), according to a study.

At 1-year follow-up, DOACs significantly correlated with elevated risks for ischaemic stroke (risk difference [RD], 4.97 percentage points, 95 percent confidence interval [CI], 1.27‒8.57; risk ratio [RR], 1.22, 95 percent CI, 1.05‒1.41) and composite stroke (RD, 5.56 percentage points, 95 percent CI, 1.77‒8.97; RR, 1.23, 95 percent CI, 1.07‒1.42) and with a reduced MI risk (RD, ‒1.61 percentage points, 95 percent CI, ‒3.17 to ‒0.03; RR, 0.61, 95 percent CI, 0.37‒0.99) compared with warfarin.

Specifically, rivaroxaban use resulted in an increased risk for ischaemic stroke during both short- and long-term follow-up periods. The risk for bleeding or all-cause death did not significantly differ between the two treatment groups.

This observational cohort study used population-wide insurance claims data in Taiwan from patients with AF-MS prescribed either DOACs or warfarin between 1 January 2011 and 31 December 2021. The authors measured the absolute RDs and RRs at 1 and 5 years of follow-up for ischaemic stroke, systemic embolism, composite stroke, MI, intracranial haemorrhage, gastrointestinal bleeding, bleeding at other critical sites, and all-cause death.

The study was limited by its relatively small sample size, lack of detailed information of MS severity, and lack of international normalized ratio measurements.