Anticoagulation remains underused in prevention of stroke associated with atrial fibrillation: Insights from two consecutive national surveys

Background: Atrial fibrillation (AF) is a major risk factor of ischemic stroke. We tested whether the adoption of the CHADS ₂ score in clinical guidelines has impacted treatment strategies for stroke prevention, and examined how AF affects stroke outcome. Methods: In the setting of two national surveys [National Acute Stroke Israeli Surveys; all patients hospitalized for stroke in Israel during February-March 2004, and March-April 2007] data of patients with and without AF were analyzed with respect to patient characteristics, use of anticoagulation, stroke severity, clinical course, and long-term outcome. Results: Of 3040 patients with acute ischemic stroke, 586 patients (19%) had a history of AF. Severe strokes on admission were significantly more frequent in patients with AF, as was the proportion of total anterior circulation strokes. Ischemic stroke associated with AF predicted poor outcome at discharge (adjusted OR 1.56; 95%CI 1.24-1.96) and higher mortality rates throughout follow-up. Among patients with a CHADS ₂ score 2 prior to the index stroke and without known contraindications, 41% received anticoagulation. This proportion increased to only 62% after the index stroke, even after excluding patients with severe disability and no significant increase between 2004 and 2007 was detectable. Increasing age, in-hospital infectious complications, and unfavorable functional status at discharge were independently associated with decreased likelihood of receiving anticoagulation. Conclusions: In deviation from current recommendations and in spite of the introduction of CHADS ₂ criteria, anticoagulation for stroke prevention remains underutilized, despite the particularly poor outcome of strokes associated with AF.