Gender impacts mortality after traumatic brain injury in teenagers

BACKGROUND: Gender may influence outcomes following traumatic brain injury (TBI) although the mechanism is unknown. Animal TBI studies suggest that gender differences in endogenous hormone production may be the source. Limited retrospective clinical studies on gender present varied conclusions. Pediatric patients represent a unique population as pubescent children experience up-regulation of endogenous hormones that varies dramatically by gender. Younger children do not have these hormonal differences. The aim of this study was to compare pubescent and prepubescent females with males after isolated TBI to identify independent predictors of mortality. METHODS: We performed a retrospective review of the National Trauma Data Bank Research Data Sets from 2007 and 2008 looking at all blunt trauma patients 18 years or younger who required hospital admission after isolated, moderate-to-severe TBI, defined as head Abbreviated Injury Scale (AIS) score 3 or greater. We excluded all individuals with AIS score of 3 or greater for any other region to limit the confounding effect of comorbidities. Based on the median age of menarche, we defined two age groups as follows: prepubescent (0-12 years) and pubescent (>12 years). Analysis was performed to compare trauma profiles and outcomes between groups. Our primary outcome measure was in-hospital mortality. RESULTS: A total of 20,280 patients met inclusion criteria; 10,135 were prepubescent, and 10,145 were pubescent. Overall mortality was 6.9%, and lower mortality was noted among prepubescent patients compared with pubescent (5.2% vs. 8.6%, p < 0.0001). Although female gender did not predict reduced mortality in the prepubescent cohort (adjusted odds ratio, 1.05; 95% confidence interval, 0.85-1.30; p = 0.63), female gender was associated with reduced mortality in the pubescent (adjusted odds ratio, 0.78; 95% confidence interval, 0.65-0.93; p = 0.007). CONCLUSION: In contrast to prepubescent female gender, pubescent female gender predicts reduced mortality following isolated, moderate-to-severe TBI. Endogenous hormonal differences may be a contributing factor and require further investigation. LEVEL OF EVIDENCE: Prognostic study, level III.