DOACs Reduce Cardiovascular Events in Lower-Risk Atrial Fibrillation

In the SINGLE-AF trial, patients with atrial fibrillation and one thromboembolic risk factor who received a direct oral anticoagulant had a lower rate of composite cardiovascular events at 24 months than those without anticoagulation. The absolute risk difference was small, with annual stroke incidence under 1% in the control group, leading researchers to caution that the benefit may be overestimated. Major bleeding rates were similar between groups, but the low number of events limited the precision of the findings.

The SINGLE-AF trial enrolled men and women with atrial fibrillation and exactly one CHA₂DS₂-VASc risk factor beyond sex, such as hypertension, diabetes, or age 65 or older. Over 24 months, the composite cardiovascular event rate was 0.5% with a DOAC versus 1.5% without, though annual stroke incidence remained below 1% in the untreated group. Major bleeding occurred similarly between arms, but the sparse events limited statistical certainty. The authors and an accompanying editorial emphasized that the apparent benefit may be inflated, and that individual stroke, embolism, and bleeding outcomes were not definitively different. The trial is the first randomized evidence favoring DOACs in this intermediate-risk population, yet guidelines currently assign only a class IIa recommendation for such patients.