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Stroke severity in atrial fibrillation. The Framingham Study
H J Lin1, P A Wolf, M Kelly-Hayes
1Department of Neurology, Boston University School of Medicine, MA 02118, USA.
Insights
Atrial fibrillation (AF) stroke is nearly twice as fatal as non-AF stroke, with higher recurrence and severe functional deficits. Early prevention of AF-related stroke is critical for reducing mortality and disability.
Area of Science:
- Cardiology
- Neurology
- Epidemiology
Background:
- Clinical series suggest stroke with atrial fibrillation (AF) is more severe.
- Prospective epidemiological data on AF-related stroke outcomes are limited and inconsistent.
Purpose of the Study:
- To investigate the long-term impact of atrial fibrillation on stroke severity and outcomes.
- To compare mortality and functional status of ischemic stroke in patients with and without AF.
Main Methods:
- Analysis of over 40-year follow-up data from the Framingham cohort (5070 participants).
- Evaluation of 501 initial ischemic strokes, including 103 with AF, assessing severity and 30-day mortality.
- Functional status assessed using the Barthel index since 1981 for acute and 12-month follow-up.
Main Results:
- AF was linked to increased stroke severity (P = .048) and higher 30-day mortality (25% vs. 14%).
- Multivariate analysis showed an 84% increased odds of 30-day mortality for AF-related strokes (OR, 1.84).
- AF stroke survivors experienced poorer survival, more recurrences, and significantly lower Barthel index scores up to 12 months post-stroke.
Conclusions:
- Ischemic stroke in patients with AF is nearly twice as likely to be fatal compared to non-AF stroke.
- AF is associated with increased stroke recurrence and more severe functional deficits in survivors.
- Given that stroke is often the initial embolic event in AF, preventive strategies are crucial to mitigate disability and mortality.
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 chi 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.