Gender-related differences in intracranial hypertension and outcome after traumatic brain injury

Background We have previously studied possible gender-related differences in intracranial hypertension and outcome following head injury. The results were always close to the limit of significance so that to achieve greater statistical power we have continued recruitment of patients for further 5 years. Methods Head injury patients (612) who were sedated and ventilated were studied from 1992—2007. All had intracra-nial pressure (ICP), arterial blood pressure (ABP) and cerebral perfusion pressure (CPP) monitored continuously. Patients' outcome was assessed at 6 months post-injury (469 were available for follow-up).

Results This retrospective analysis enrolled 98 females and 371 males. Males and females were well matched for age (mean±standard deviation: 33±17 and 33±16 years respectively) and the initial median Glasgow Coma Score (GCS) [females and males 6]. The difference in mortality rate between sexes was age-related. In the subgroup of patients younger than 50 years mortality was 17% in males and 29% in females (p=0.026), whereas there was no difference above 50 years (around 40% both males and females). Mean ICP, CPP and ABP were not different between males and females. However, cerebrovascular pressure reactivity was found to be significantly worse in females than in males in the age group below 50 years (PRx; males: 0.044±0.031; females 0.11±0.047; p<0.05). Conclusion Following head injury females younger than 50 have a significantly worse pressure reactivity and greater mortality rate than males of the same age.