Sex-related time-dependent variations in post-stroke survival-evidence of a female stroke survival advantage

Background: Women live longer than men, yet most studies show that gender has no influence on survival after stroke. Methods: A registry was started in 2001, with the aim of registering all hospitalized stroke patients in Denmark, and it now holds 39,484 patients of which 48% are female. We studied the influence of gender on post-stroke mortality, from the time of admission through the subsequent years until death or censoring ( mean follow-up time: 538 days).

All patients underwent an evaluation including stroke severity, computed tomography and cardiovascular risk factors. Independent predictors of death were identified by means of a survival model based on 22,222 individuals with a complete data set. Results: Females were older and had severer stroke. Interestingly, the risk of death between genders was time dependent.

The female/male stroke mortality rate favoured women from the first day of stroke and remained so during the first month suggesting a female survival advantage. Throughout the second month the rate reversed in favour of men suggesting that women in that period are paying a 'toll' for their initial survival advantage.

Hereafter, the rate steadily decreased, and after 4 months women continued to have the same low risk as in the first week. Conclusions: Our study suggests a female superiority in stroke survival competence.