- Design
- Multicentre, open-label, adjudicator-masked randomised superiority trial
- Population
- 1,803 patients with AF and CHA2DS2-VASc 1 (men) or 2 (women), mean age 60.4
- 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 to 0.94)
Current US and European guidelines give oral anticoagulation a class IIa recommendation for atrial fibrillation at intermediate stroke risk, without randomised trial evidence behind it. SINGLE-AF tested the question in a multicentre, open-label, adjudicator-masked trial in South Korea.
It randomised 1,803 patients with CHA2DS2-VASc of 1 in men or 2 in women to a DOAC (902) or no anticoagulation (901). Mean age was 60.4 years and 23.7% were women. The primary end point was a composite of stroke, systemic embolism, major bleeding or cardiovascular death at 24 months.
It occurred in 4 patients (0.5%) on a DOAC and 13 (1.5%) without (difference -1.0 percentage points, 95% CI -2.0 to -0.1; HR 0.31, 95% CI 0.10 to 0.94; P=0.03). Stroke occurred in 3 vs 10. Systemic embolism and major bleeding appeared similar between groups, and there were no cardiovascular deaths. Serious adverse events were 8.9% vs 9.3%.
The result supports the existing recommendation rather than replacing it, but it rests on 17 events in a younger, largely male, East Asian population. The guideline has not changed.
- Calculate CHA2DS2-VASc and bleeding risk at every AF review; intermediate risk (1 in men, 2 in women) is where this trial applies.
- Discuss DOAC therapy with intermediate-risk patients as supported by this trial and by current class IIa guidance.
- Absolute benefit was small: about 1 percentage point over 2 years in the primary composite.
- Record the patient's own preference and bleeding risk factors in the shared decision.
Why it matters
It adds randomised evidence for a guideline recommendation that had little behind it for patients at intermediate stroke risk.
Don't overread it
Open-label design, 17 primary events and a single-country population limit how far the result travels, including to Indian patients.
The statistics, in plain English
An upper confidence limit of 0.94 for the hazard ratio means the result only just excludes no effect, and with 17 events in total it is fragile. The absolute difference of 1.0 percentage point (interval 0.1 to 2.0) is a more honest guide to size than the relative figure.
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