HealthDay News — One additional stroke risk factor is associated with a significant increase in event rates among untreated low-risk patients with nonvalvular atrial fibrillation (CHA2DS2-VASc = 0 [male], 1 [female]), according to a study published in the Journal of the American College of Cardiology.

Gregory Y.H. Lip, MD, from Aalborg University in Denmark, and colleagues examined the risk of stroke and bleeding and the impact of antithrombotic therapy among low-risk patients. Data were included for 39,400 patients discharged with incident nonvalvular atrial fibrillation with 0 or 1 CHA2DS2-VASc risk factors. Of these, 23,572 were not treated, while 5,353 and 10,475 were started on aspirin and warfarin, respectively.

The researchers found that for untreated low-risk patients (CHA2DS2-VASc = 0 [male], 1 [female]), stroke event rates were 0.49 and 0.47 per 100 person-years at one-year and at full-time follow-up, respectively. Among untreated low-risk patients, bleeding event rates were 1.08 per 100 person-years at one year and 0.97 at full follow-up. Among untreated patients, the presence of one additional risk factor (CHA2DS2-VASc = 1 [male], 2 [female]) increased the stroke rate 3.01-fold to 1.55 per 100 person years at one year. Bleeding and death were increased 2.35- and 3.12-fold, respectively, at the one-year follow-up.

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“With one additional stroke risk factor (CHA2DS2-VASc = 1 [male], = 2 [female]), there was a significant increase in event rates (particularly mortality) if nonanticoagulated,” the authors write.

Several authors disclosed financial ties to the pharmaceutical industry.


  1. Lip GYH et al. J Am Coll Cardiol. 2015; doi:10.1016/j.jacc.2015.01.044.