Stroke Severity in Atrial Fibrillation: The Framingham Study

Abstract

Background and Purpose Stroke occurring with atrial fibrillation (AF) is more likely to be fatal or more severe than non-AF stroke based on clinical series, but data from prospective epidemiological studies are sparse and inconsistent. Methods Over 40-year follow-up of the original 5070 Framingham cohort, 501 initial ischemic strokes, including 103 with AF, were analyzed. Stroke severity was rated as none, mild, moderate, severe, or fatal. Since 1981, functional status indicated by the Barthel index has been evaluated acutely and at 3, 6, and 12 months. Severity and functional status of AF strokes were compared with non-AF strokes using χ 2 test and Student's t test. Thirty-day mortality was assessed by logistic regression analyses. Results AF was associated with increased stroke severity ( P =.048). Thirty-day mortality was greater in AF strokes than in non-AF strokes (25% versus 14%). The multivariate-adjusted odds ratio for 30-day mortality for AF subjects was 1.84 (95% confidence interval, 1.04 to 3.27). Since 1981, follow-up was available for 150 initial ischemic strokes, including 30 with AF. Compared with the non-AF group, the AF group had poorer survival and more recurrences during 1 year of follow-up. The AF subjects had lower mean Barthel index scores acutely (29.6 versus 58.6, P <.001) and at 3 months ( P =.005), 6 months ( P =.003), and 12 months ( P =.130) after stroke among survivors. Conclusions Ischemic stroke associated with AF was nearly twice as likely to be fatal as non-AF stroke. Recurrence was more frequent, and functional deficits were more likely to be severe among survivors. Since stroke is usually the initial manifestation of embolism in AF, prevention is critical to reducing disability and mortality.