Sex Differences in Stroke Risk Among Older Patients With Recently Diagnosed Atrial Fibrillation
Does gender affect the risk of stroke in patients with atrial fibrillation (AF)?
This was a retrospective database cohort study of 83,513 patients 65 years or older (mean age 79 years, 47.2% men) with a discharge diagnosis of AF in Quebec in 1998-2007. The CHADS2 score was determined for each patient, based on secondary discharge diagnoses. The primary outcome was stroke.
The mean CHADS2 score was significantly higher in women (1.99) than men (1.74). In patients 75 years or older, warfarin was prescribed in 58.9% of women and 56.4% of men. In patients younger than 75 years, warfarin was prescribed in 65.4% of women and 61.1% of men. Under the age of 75 years, there was no difference in the stroke incidence between women (1.23/100 patient-years) and men (1.20/100 patient-years). In patients 75 years or older, the stroke incidence was significantly higher in women (2.38/100 patient-years) than in men (1.95/100 patient-years). By multivariate analysis, female gender was associated with a 14% higher risk of stroke compared to men, independent of comorbidities and warfarin therapy. The rate of intracerebral hemorrhage was similar in men and women (~1.4%).
The authors concluded that among patients with AF 75 years or older, women are at greater risk of stroke than men, even when treated with warfarin.
This study confirms that female gender is an independent risk factor for stroke. A limitation of the CHADS2 score is that it does not take gender into consideration. Because the CHA2DS2-VASc score assigns 1 point for female gender, it is more effective for identifying patients with a low CHADS2 score who are at risk of stroke.
Keywords: Stroke, Ischemic Attack, Transient, Multivariate Analysis, Health Resources, Warfarin, Comorbidity, Risk Factors, Incidence, Naphthalenes, Atrial Fibrillation, Cerebral Hemorrhage
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