The independent effect of gender on outcomes following traumatic brain injury: a preliminary investigation.

Although epidemiological studies of gender differences in outcome after brain injury are limited, studies in animals indicate higher fatality rates for females. Studies in which healthy human brain metabolism was investigated also suggest gender differences. In this paper the authors examine gender as an independent predictor of survival following brain injury. A prospective cohort of severely and moderately brain injured individuals was identified from two trauma centers over a period of 3.5 years. Patients enrolled in the cohort were followed for as long as 18 months postdischarge. The Glasgow Outcome Scale was used to measure long-term outcome. Overall, mortality was 1.28 times higher in females than males, with the greatest difference of 2.14 found in deaths postdischarge. Controlling for age, admission Glasgow Coma Score, penetrating as compared with blunt injury, and the presence of multiple trauma, females were 1.75 times more likely than males to die of their brain injury (95% confidence interval 1.09-2.82). Furthermore, females were 1.57 times more likely to experience poor outcomes (that is, severe disability or persistent vegetative state) than males. These findings suggest the need to examine similar effects in different cohorts and to identify the pathophysiological basis for the differences observed in this epidemiological study.