Gender disparity in ventilator-associated pneumonia following trauma: identifying risk factors for mortality

Abstract

Background: Gender alone offers no survival advantage in humans following trauma. However, male gender does predict increased morbidity, specifically ventilator-associated pneumonia (VAP). Previous work has shown that despite lower incidence of VAP, females with VAP have increased mortality. The purposes of this study were to evaluate the impact of VAP and gender on outcome and to determine which characteristics of severe VAP predict mortality in trauma patients.

Methods: Patients with VAP (≥10 colony-forming units per milliliter in bronchoalveolar lavage) over 8 years were stratified by gender, age, severity of shock, and injury severity. Severe VAP factors were defined as multiple-episode, polymicrobial, multidrug-resistant, nosocomial VAP diagnosed within 7 days of admission (eNVAP), and multiple inadequate empiric antibiotic therapy episodes. Mortality and severe VAP factors were compared using χ analysis. Multivariable logistic regression (MLR) was performed to determine which VAP factors were independent predictors of mortality.

Results: A total of 854 patients were identified, 676 men (79%) and 178 women (21%). Despite a higher incidence of VAP among males (3.8% vs. 2.6%, p = 0.001), mortality was higher in females (24% vs. 15%, p = .009). All characteristics of severe VAP were increased in females except multiple episodes (p = 0.15). MLR identified eNVAP as an independent predictor of mortality in females with severe VAP after adjusting for age, Glasgow Coma Scale (GCS) score, Injury Severity Score (ISS), admission base excess, and 24-hour transfusions (odds ratio, 9.97; p = 0.001).

Conclusion: That females develop less VAP but experience increased mortality confirms previous studies. Characteristics of severe VAP are increased in females and may contribute to this observed mortality difference. MLR identified eNVAP as an independent predictor of mortality in females with severe VAP following trauma.

Level of evidence: Epidemiologic/prognostic study, level III.