Female survival advantage relates to male inferiority rather than female superiority: A hypothesis based on the impact of age and stroke severity on 1-week to 1-year case fatality in 40,155 men and women.
Background: It is generally believed that differences in age, stroke characteristics, and cardiovascular risk factors account for observed sex-specific differences in stroke survival. Objectives: We aimed to study female stroke survival advantage before and after the average age of menopause, and whether female survival advantage applies only to patients for whom stroke is the most likely cause of death. Methods: The Danish National Indicator Project, a registry designed to list all hospitalized stroke patients in Denmark beginning in March 2001, had 40,155 registered patients as of February 2007. All registered patients had undergone evaluation including stroke severity (as measured by the Scandinavian Stroke Scale [SSS], using a total score of 0-58, in which lower scores indicate more severe strokes), computed tomography, and cardiovascular risk factors. Patients were followed from admission until death or censoring. Case fatality (stratified by 1 week, 1 month, 3 months, and 1 year) in men and women was correlated with age and stroke severity. Adjustment for cardiovascular risk factors was performed by means of multivariate regression analysis. Results: A total of 20,854 (51.9%) men and 19,301 (48.1%) women were registered. Women were significantly older than men at the time of stroke (74.5 vs 69.7 years, respectively; P