Differences in stroke outcome based on sex

Objective — Stroke thrombolysis may have a differential effect by sex. We sought to examine the relationship between sex and outcome after thrombolysis.

Methods — This is a retrospective cohort study of stroke patients from the Registry of Canadian Stroke Network phase 1 (June 2001-February 2002) and phase 2 (June 2002-December 2002). Variables including demographics, history, clinical data, process measures, and outcome were analyzed. The primary outcomes were the Stroke Impact Scale-16 score (SIS-16) and mortality at 6 months. We compared the outcomes of the thrombolyzed and nonthrombolyzed cohorts and examined the data for a tissue plasminogen activator (tPA)-by-sex interaction on the 2 primary outcomes.

Results — The overall proportion of patients who achieved an excellent outcome (SIS-16 >75) was not different by gender. However, the proportion of patients achieving an excellent outcome in the non-tPA cohort was much greater in males, with an absolute risk difference of 11.8%. A multiplicative treatment by sex interaction was evident (p = 0.054). This interaction was not present for stroke case fatality.

Conclusions — Women fared poorly compared to men in the placebo groups, but this negative prognostic sex effect was neutralized by thrombolysis.