A big study in South Korea tested newer blood thinners on people with atrial fibrillation who have a medium chance of stroke.
The study, called SINGLE‑AF, was shown at the ESC Congress 2026 and printed in the New England Journal of Medicine. It compared people who took a pill with those who took nothing.
Why This Matters
Atrial fibrillation, or AF, is an irregular heartbeat that can cause clots, stroke, and other heart problems. Doctors usually give blood thinners to patients with a high risk of stroke. For patients with a medium risk, the advice has been unclear.
Older studies using vitamin‑K drugs gave mixed results, leaving doctors unsure.
Professor Boyoung Joung, who led the trial, said the research was needed to see if the newer pills work better for medium‑risk patients.
How the Study Was Done
The trial included 1,803 AF patients from 18 hospitals. All had a CHA₂DS₂‑VASc score of 1 (men) or 2 (women), which means medium risk.
Participants were split into two groups. One group took a direct oral anticoagulant – either apixaban 5 mg twice a day or rivaroxaban 20 mg once a day. The other group received no anticoagulant.
Big Drop in Bad Events
After two years, the group on the newer pills had 69 % fewer serious outcomes. The main outcome counted stroke, clots, big bleeds, and death from heart problems.
Only 0.5 % of the pill group had a serious event, compared with 1.5 % of the no‑pill group.
Most of the benefit came from fewer ischemic strokes: 0.1 % with pills versus 1.1 % without.
Major bleeding was not higher. It happened in 0.3 % of the pill group and 0.5 % of the no‑pill group.
What This Means
The findings give strong proof that modern blood thinners help patients with AF who have a medium stroke risk, and they do not cause extra bleeding.
Professor Joung said the results could change future treatment guidelines and insurance rules.