Sex-Related Differences in the Risk of Hospital-Acquired Sepsis and Pneumonia Post Acute Ischemic Stroke

Background and Objective: Infectious complications after ischemic stroke are frequent and lead to neurological deterioration, poor functional outcomes, and higher mortality. Local and systemic inflammatory responses to brain ischemia differ between males and females, but little is known about differences in poststroke susceptibility to infection by sex. The purpose of this study was to compare sex-related differences in the risk of hospital-acquired sepsis and pneumonia after acute ischemic stroke (AIS). Materials and Methods: This is a retrospective, secondary analysis of the 2010-2011 California State Inpatient Database. Previously validated International Classification of Disease, Ninth Revision (ICD-9) codes were used to identify adult hospitalizations for AIS. The primary outcome was hospital-acquired sepsis or pneumonia, also identified using ICD-9 codes. Associations between sex and hospital-acquired sepsis or pneumonia were adjusted for baseline characteristics and comorbidities using multivariable logistic regression. Results: There were 91,643 hospitalizations for AIS included in this analysis, of which 1027 had hospital-acquired sepsis and 1225 had hospital-acquired pneumonia. The in-hospital mortality without infection was 4.6%; the presence of hospital-acquired infections was associated with higher mortality for sepsis (32.7%) and pneumonia (21.9%). Female (versus male) sex was associated with lower adjusted odds of hospital-acquired sepsis (odds ratio [OR].74, 95% confidence interval [CI].65-.84) and pneumonia (OR.69, 95% CI.62-.78). This difference was similar across age strata. Among hospitalizations with either hospital-acquired sepsis or pneumonia, sex did not influence mortality. Conclusions: Female sex was associated with a lower risk of hospital-acquired sepsis and pneumonia after AIS. Further investigation is needed to determine the mechanisms underlying this clinical observation.