DOACs reduced events at intermediate stroke risk in atrial fibrillation

Design

Multicentre, open-label, adjudicator-masked randomised superiority trial

Population

1803 patients with AF and CHA2DS2-VASc 1 (men) or 2 (women), South Korea

Primary outcome

Stroke, systemic embolism, major bleeding or cardiovascular death at 24 months

Effect

0.5% vs 1.5%, difference −1.0 points (95% CI −2.0 to −0.1); HR 0.31 (0.10–0.94)

SINGLE-AF randomised 1803 patients in South Korea with atrial fibrillation and a CHA2DS2-VASc score of 1 in men or 2 in women to a DOAC or no anticoagulation. The trial was open-label with masked adjudication. Mean age was 60 and fewer than a quarter were women. The primary composite at 24 months was stroke, systemic embolism, major bleeding or cardiovascular death. It was published at the end of August 2026.

The composite occurred in 0.5% on a DOAC and 1.5% without (HR 0.31). Stroke occurred in 3 and 10 patients respectively. Major bleeding and systemic embolism were similar, there were no cardiovascular deaths, and serious adverse events were about 9% in both groups.

This is the first randomised support for the class IIa recommendation to anticoagulate at intermediate risk. It moves the conversation from 'may consider' towards 'should offer'. The absolute benefit is small, about one event prevented per hundred patients over two years, so the patient's view still matters. For Indian patients, affordability of DOACs over many years is part of that discussion.

• Offer a DOAC to men with CHA2DS2-VASc 1 and women with 2, rather than leaving it undecided
• Explain the absolute benefit: about one event prevented per 100 patients over two years
• Check renal function and bleeding risk before starting
• Discuss long-term cost and adherence, especially where DOACs are paid out of pocket
• Do not use aspirin as a substitute for anticoagulation

Why it matters

Anticoagulation at intermediate stroke risk now has randomised evidence behind it rather than extrapolation.

Don't overread it

Only 17 primary events occurred and the trial was open-label in a young, mostly male Korean cohort, so the size of the effect is uncertain.

The statistics, in plain English

HR 0.31 (95% CI 0.10–0.94) looks like a 69% reduction, but it rests on 17 events in total, which is why the interval runs from a 90% to a 6% reduction. The absolute difference was 1.0 percentage point (−2.0 to −0.1). A result that just excludes no effect on so few events is less secure than its hazard ratio suggests.

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