Use of a pediatric cohort to examine gender and sex hormone influences on outcome after trauma

BACKGROUND: Animal studies suggest that female gender imparts a protective effect on outcome after trauma, and implicate sex hormones as the cause. Human studies have yielded mixed results. These results are confounded by postmenopausal hormone replacement and the difficulty of controlling for pretrauma comorbidities. The pediatric population is a better model to determine the impact of gender and sex hormones on outcome after trauma. METHODS: The National Trauma Data Bank was queried for all patients from birth to 20 years of age. Age, gender, Injury Severity Score (ISS), mechanism of injury, mortality, intensive care unit days, and ventilator days were examined. To control for the effect of sex hormones, patients were divided into three groups by age: prepubertal (birth to 8 years), peripubertal (8.1-14.5 years), and postpubertal (14.6-20 years). We calculated survival rates for age group ISS subsets overall and by mechanism of injury. RESULTS: The prepubertal and peripubertal age groups had equivalent survival rates between genders across all severities of injury. The sex hormone-containing postpubertal cohort had a significantly improved survival rate for women across all ISS subgroups, and the effect was more pronounced with increasing ISS. This effect was despite a higher mean ISS for women at these greater magnitudes of injury. The cause of this effect could not be explained by mechanism of injury, ventilator days, or intensive care unit days. CONCLUSION: Female gender was associated with improved survival rates for patients demonstrating sex hormone production (i.e. postpubescent patients) in a manner that was directly proportional to their severity of injury. No protective effect of gender was seen in the prepubescent or peripubertal age groups.