A statewide population-based study of gender differences in trauma: Validation of a prior single-institution study

BACKGROUND: Women usually have lower mortality rates than men do at any age. This pattern is observed for most causes of death from chronic diseases. Significant controversy still exists about gender differences in outcomes in trauma. We previously reported no differences in in-hospital mortality based on gender in a large single-institution study (n = 18,892) that had a significant limitation in that it was not population based. This current study was performed to validate our earlier findings in a separate, statewide, population-based dataset of trauma victims. STUDY DESIGN: Prospective data were collected on 22,332 trauma patients (18,432 blunt, 3,900 penetrating) admitted to all trauma centers (n = 26) in Pennsylvania over 24 months (January 1996 to December 1997). Gender differences in in-hospital mortality were determined for the entire dataset and for the subsets of blunt and penetrating injury patients. A second analysis examined all blunt injury patients and excluded all patients with a hospital length of stay of less than 24 hours, eliminating patients who expired soon after admission. The null hypothesis was that female gender is protective in trauma outcomes. RESULTS: Multiple logistic regression analysis identified age (odds ratio [OR] 1.03, confidence interval [CI] 1.02 to 1.03), Injury Severity Score (OR 1.06, CI 1.05 to 1.06), non-Caucasian race (OR 1.72, CI 1.39 to 2.15), blunt injury type (OR 0.327, CI 0.26 to 0.41), and Revised Trauma Score (OR 0.44, CI 0.41 to 0.47) as independent predictors of in-hospital mortality in trauma. Preexisting diseases, including cardiac disease (OR 1.53, CI 1.12 to 2.09) and malignancy (OR 4.08, CI 1.64 to 10.17), were also identified as independent predictors of in-hospital mortality in trauma. Female gender was not associated with decreased mortality (OR 0.83, CI 0.67 to 1.03, p = 0.093). A second multiple regression analysis in blunt trauma patients admitted for longer than 24 hours (which eliminated early deaths and patients with minor injuries) determined that in-hospital mortality was not significantly different in male or female blunt trauma patients stratified by Injury Severity Score and age. The same factors that were predictive of in-hospital mortality in the total dataset were also significant in this secondary analysis. CONCLUSIONS: These population-based data confirm that female gender does not adversely affect in-hospital mortality in trauma when patients are appropriately stratified for other variables, including Injury Severity Score and age, that do significantly affect outcomes.