Sex Differences in Stroke Risk Among Older Patients With Recently Diagnosed Atrial Fibrillation

Study Questions:

Does gender affect the risk of stroke in patients with atrial fibrillation (AF)?

Methods:

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.

Results:

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%).

Conclusions:

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.

Perspective:

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.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Anticoagulation Management and Atrial Fibrillation, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: Stroke, Ischemic Attack, Transient, Multivariate Analysis, Health Resources, Warfarin, Comorbidity, Risk Factors, Incidence, Naphthalenes, Atrial Fibrillation, Cerebral Hemorrhage


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