DOAC benefit shown in AF at intermediate stroke risk

Design

Multicentre, open-label, adjudicator-masked RCT

Population

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

Primary outcome

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

Effect

0.5% vs 1.5%; HR 0.31 (95% CI 0.10 to 0.94)

SINGLE-AF randomised 1803 patients in South Korea with atrial fibrillation and CHA2DS2-VASc 1 in men or 2 in women to a DOAC or no anticoagulation. It was open-label with masked adjudication; mean age was 60 and 24% were women. It was published in NEJM in August.

At 24 months the composite of stroke, systemic embolism, major bleeding or cardiovascular death occurred in 0.5% on a DOAC and 1.5% without (difference −1.0 percentage point, 95% CI −2.0 to −0.1; HR 0.31, 0.10 to 0.94). Stroke occurred in 0.3% versus 1.1%. Major bleeding and systemic embolism appeared similar, with no cardiovascular deaths. Serious adverse events were 8.9% versus 9.3%.

US and European guidelines give anticoagulation at this risk level a class IIa recommendation without randomised support. This is that support, in an East Asian population with a lower bleeding signal than feared. Absolute benefit is about one event prevented per 100 patients over two years, so the decision remains shared. In India, DOAC cost over a lifetime is a real factor; generic dabigatran, rivaroxaban and apixaban lower it.

• Offer a DOAC to patients with CHA2DS2-VASc 1 (men) or 2 (women) after assessing bleeding risk.
• Explain the absolute benefit: about 1 in 100 fewer events over two years.
• Use guideline DOAC doses; avoid off-label under-dosing.
• Record the decision and revisit it if the score or bleeding risk changes.

Why it matters

A class IIa recommendation that rested on observational data now has a randomised trial behind it.

Don't overread it

With 17 events the size of the benefit is uncertain; the direction is the finding.

The statistics, in plain English

There were only 17 primary events in total, so the hazard ratio of 0.31 is imprecise: the interval (0.10 to 0.94) runs from a large to a marginal benefit. The absolute difference is 1 percentage point over 24 months. Including major bleeding in the composite means the result reflects benefit net of bleeding. The population was Korean, younger and mostly male.

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