Impact of Sex Difference on Severity and Functional Outcome in Patients with Cardioembolic Stroke

Introduction: Female sex is a risk factor for thromboembolic events in Caucasian, but not in Japanese, patients with nonvalvular atrial fibrillation. However, it remains unclear whether the female sex is also a risk factor for severe stroke and unfavorable functional outcome in patients with cardioembolic (CE) stroke. Methods: Three hundred fifty-five consecutive patients with CE stroke within 48 hours after onset and with a modified Rankin Scale (mRS) score of 1 or lower before onset were studied. We compared basic characteristics, stroke severity, and functional outcome between female (n = 157) and male (n = 198) patients. Results: The mean age was higher in female than in male patients (80 +/- 8 versus 75 +/- 9 years, P < .00001). The congestive heart failure, hypertension, age [= 75 years], diabetes, stroke/transient ischemic attack [TIA] (CHADS(2)) score before onset was similar between the two groups (median, 3 [2-4] in both groups). Stroke severity on admission, assessed by the National Institutes of Health Stroke Scale (NIHSS), was higher in female than in male patients (13 [5-20] versus 8 [3-16], P = .0009). Functional outcome at discharge, assessed by mRS, was unfavorable in female than in male patients (3 [1-5] versus 2 [1-4], P = .005). An mRS score of 3 or higher at discharge was found more in female than in male patients (59% versus 39%, P = .0001). Multivariate analyses confirmed that female sex was a significant determinant of severe stroke (NIHSS = 8) on admission (odds ratio [OR] to male = 1.97; 95% confidence interval [CI]; 1.24-3.15, P = .004) and for the mRS score of 3 or higher at discharge (OR = 1.83; 95% CI, 1.16-2.89; P = .01). Similar results were obtained by propensity-score matching analysis. Conclusions: Female sex is a risk factor for severe stroke on admission and unfavorable functional outcome at discharge in Japanese patients with CE stroke.