Factors Mediating Outcome After Stroke: Gender, Thrombolysis, and Their Interaction

Abstract

Several studies, but not all, have shown that women benefit more from intravenous thrombolysis than men; few have accounted for pre-stroke mobility. Our aim was to determine whether there was an interaction between gender and thrombolysis treatment in 3-month modified Rankin Scale (mRS) score, after adjusting for pre-stroke mobility. We retrospectively reviewed medical records of 1390 consecutive ischemic stroke patients admitted between October 2012 and July 2015. The 3-month mRS was obtained from clinic visits. Thrombolysis-by-gender interaction was evaluated in univariate and multivariate analyses using ordinal logistic ("shift") regression with the full mRS range from 0 to 6 as the dependent variable. We included 926 (456 women and 470 men) patients with follow-up. Women were older (mean age 68.1 vs 65.8 years, P = 0.013), less likely to be treated with thrombolysis (15.6 vs 24.0%, P = 0.002), less often discharged to home (49.1 vs 59.6%, P = 0.001), and more likely to use ambulation aids pre-stroke (13.6 vs 8.5%, P = 0.014).Women had worse outcomes than men in those not treated with thrombolysis (mRS 3: 55.1 vs 40.1%, P < 0.001). In those who received thrombolysis, there were no gender differences (47.9 vs 50.4%, P = 0.736). In multivariable modeling, there was a significant gender-treatment interaction (P < 0.001), after adjustment for gender, pre-stroke ambulation aid use, age, age-by-gender interaction, initial stroke severity, diabetes, heart failure, and prior stroke. Our results show that women benefit from thrombolysis more than men, and the thrombolysis-by-gender interaction persists after adjustment for pre-stroke mobility impairment.