Background: Accumulating clinical and epidemiological evidence suggests significant gender differences in the incidence of and outcome following major infection. In a rodent model of hemorrhagic shock, investigators have shown that males manifest depressed cell-mediated immunity that is reversed by castration or pharmacologic testosterone receptor blockade. Female rats, in contrast, show enhanced immune function that is reduced to male levels by testosterone administration. This sexual dimorphism is believed responsible for the improved outcome in female mice following septic challenge.
Hypothesis: Male gender is a risk factor for major infections following severe injury.
Design: Five-year prospective cohort study ending October 1998.
Setting: Urban level I regional trauma center.
Patients and methods: A total of 545 trauma patients older than 15 years with an Injury Severity Score greater than 15 and survival more than 48 hours were prospectively identified and studied. Collected data included age, injury mechanism, and Injury Severity Score. Major infections, defined as pneumonia, abdominal and pelvic abscess, wound infection requiring operative debridement, and meningitis, were tabulated. The occurrence of major infections in males and females was compared using multiple logistic regression analysis.
Main outcome measure: Postinjury major infectious complications.
Results: Of the 545 patients, 135 (24.8%) were female and 410 (75.2%) were male. Major infections occurred in 219 (40.2%) patients. Logistic regression confirmed that male gender is an independent risk factor for major infections (P=.04) after controlling for age and Injury Severity Score. Males had a 58% greater risk of developing a major infection (odds ratio, 1.58; 95% confidence interval, 1.01-2.48).
Conclusions: Male gender is associated with a dramatically increased risk of major infections following trauma. This effect is most significant following injuries of moderate severity (Injury Severity Score 16-25) and persists in all age groups.