Blood thinners cut events in intermediate-risk AF trial

At 18 centers in South Korea, researchers put a practical question to the test: should some people with atrial fibrillation receive an oral blood thinner even when their stroke risk is not yet classified as high? The open-label SINGLE-AF trial randomized 1,803 patients with intermediate risk to a direct oral anticoagulant—known as a DOAC—or no anticoagulation.

The DOAC group received either apixaban, 5 mg twice daily, or rivaroxaban, 20 mg once daily. After 24 months, stroke, systemic embolism, major bleeding or cardiovascular death occurred in 0.5% of patients taking a DOAC, versus 1.5% of those without anticoagulation. The trial report describes that difference as a 69% reduction in the primary endpoint.

The clearest separation came from ischemic stroke, caused by a clot blocking blood flow. Its incidence was 0.1% with DOAC therapy and 1.1% without it. Major bleeding, the main safety concern with anticoagulants, was 0.3% in the DOAC group and 0.5% in the no-anticoagulation group, with no difference reported.

So what changes in practice? Clinicians now have randomized-trial evidence to weigh when discussing anticoagulation with patients whose atrial-fibrillation stroke-risk score is intermediate, rather than relying only on conflicting observational evidence. The findings may also inform future guidelines and reimbursement policies, but they do not replace an individual treatment decision.

The boundaries are clear. SINGLE-AF was open-label, lasted 24 months, and was conducted at centers in South Korea. Its results were presented at ESC Congress 2026 and published in the New England Journal of Medicine.