Anticoagulation for Low Stroke Risk Atrial Fibrillation

Study Questions:

What is the net clinical benefit for treated atrial fibrillation (AF) patients with one nongender-related stroke risk factor (CHA2DS2-VASc = 1 for men, = 2 for women) with oral anticoagulation (OAC)?


From a community-based cohort of unselected AF patients, the authors investigated outcomes and calculated the net clinical benefit associated with OAC use in patients with zero or one nongender-related stroke risk factor. Net clinical benefit was calculated using two different methods, as done previously by Singer and Connolly. Of 8,962 patients with AF in this cohort, 2,208 (25%) had either zero or one nongender-related stroke risk factor and 45% of these patients were not prescribed OAC therapy.


During a mean follow-up of 1,028 ± 1,189 days, the yearly rate of stroke/systemic-embolism was 0.68% (95% confidence interval [CI], 0.37-1.24) for patients with no stroke risk factors and 2.09% (95% CI, 1.37-3.18) for patients with one stroke risk factor (adjusted hazard ratio, 2.82; 95% CI, 1.32-6.04). For patients with a single stroke risk factor, the net clinical benefit favors vitamin K antagonist use versus no therapy or antiplatelet drug use, but does not favor antiplatelet use versus no therapy.


The authors concluded that AF patients with only a single nongender-related stroke risk factor benefit from OAC therapy, but not antiplatelet therapy.


Since the introduction of the CHA2DS2-VASc risk scoring system, many clinicians have wondered if too many ‘low-risk’ patients were being recommended for OAC therapy and that their relatively low risk of stroke was outweighed by the bleeding risk of OAC therapy. This real-world analysis answers two important questions: 1) OAC therapy is beneficial for patients with only a single stroke risk element, and 2) antiplatelet therapy does not offer benefit for these 'low-risk' patients. Clinicians should continue to encourage OAC use among all AF patients who have at least one nongender-related stroke risk factor.

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