The effect of age and sex on outcomes following isolated moderate to severe traumatic brain injury.

Purpose: The impact of female sex on traumatic brain injury (TBI) outcomes remains controversial. The combined impact of age and sex on TBI outcomes must be clarified. We hypothesized that females have better outcomes than males in the premenopausal age group.

Methods: Data from the 2007-2016 National Trauma Data Bank of the Committee on Trauma-American College of Surgeons were used. Of a total of 686,549 patients with moderate to severe TBI (AIS ≥ 3), 251,491 were female. Comparison analyses of clinical characteristics and outcomes between females and males were conducted at different age groups: < 45 years, 45-55, and > 55 years. Logistic regressions were performed to assess the impact of age and female sex on mortality and complications.

Results: Mortality rate between females and males aged < 45 and 45-55 years was similar, but significantly reduced in the > 55 years group. After multivariate logistic regression analysis controlling for multiple confounding factors, we found that females aged > 55 years had markedly decreased risk of mortality (AOR: 0.857, 95% CI 0.835-0.879, p < 0.001) and complications.

Conclusion: Female patients in the postmenopausal stage have better outcomes following TBI than males, but pre- and perimenopausal females do not, suggesting that female sexual hormones may not provide a significant protective effect on clinical outcomes following isolated moderate to severe TBI.