Factors Influencing Sex Differences in Poststroke Functional Outcome

Abstract

Background and Purpose— Our objective was to identify factors that contribute to or modify the sex difference in poststroke functional outcome. Methods— Ischemic strokes (n=439) were identified from the Brain Attack Surveillance in Corpus Christi (BASIC) Project (2008–2011). Data were ascertained from interviews (baseline and 90 days post stroke) and medical records. Functional outcome was measured as an average of 22 activities of daily living (ADL)/instrumental ADL items (range, 1–4; higher scores worse function). Tobit regression was used to estimate sex differences and to identify confounding and modifying factors. Results— Fifty-one percent were women. Median age was 71 (interquartile range, 59–80) years in women and 64 (interquartile range, 56–77) years in men. Median ADL/instrumental ADL score at 90 days was 2.7 (interquartile range, 1.8–3.6) in women and 2.0 (interquartile range, 1.3–3.1) in men ( P <0.01); this difference remained after age-adjustment ( P <0.001). Factors contributing to higher ADL/instrumental ADL scores in women included prestroke function, marital status, prestroke cognition, nursing home residence, stroke severity, history of stroke/transient ischemic attack, and body mass index; prestroke function was the largest contributor. Stroke severity modified the sex difference in outcome such that differences were apparent for mild to moderate but not severe strokes. After adjustment, women still had significantly worse functional outcome than men. Conclusions— These findings yield insight into possible strategies and subgroups to target to reduce the sex disparity in stroke outcome; demographics and prestroke and clinical factors explained only 41% of the sex difference in stroke outcome highlighting the need for future research to identify modifiable factors that contribute to sex differences.