Gender differences in outcome in patients with hypotension and severe traumatic brain injury

Animal studies have identified hormonal influences on responses to injury and recovery, creating a potential gender effect on outcome. Progesterone and oestrogen are thought to afford protection in the immediate post-injury period, suggesting females have an advantage, although there has been limited evidence of this in human outcome studies.

This study examined the influence of gender on outcome in 229 adults (151 males), aged >17 years, with severe blunt head trauma, initial GCS <9 and hypotension, recruited into a randomised controlled trial of pre-hospital hypertonic saline resuscitation versus conventional fluid management. Outcome was measured by survival and Glasgow Outcome Scale-Extended version (GOS-E) scores at 6 months post-injury.

Females recruited into the study had a higher mean age. Females were more likely to be injured as passengers and pedestrians and males as drivers or motorcyclists. There were no gender differences in GCS or injury severity scores, ICP, cerebral perfusion pressure, gas exchange (PaO2/FiO2 ratio), or duration of mechanical ventilation. After controlling for GCS, age and cause of injury, females had a lower rate of survival. They also showed a lower rate of good outcome (GOS-E score >4) at 6 months, but this appeared to reflect the lower rate of initial survival. Those females surviving had similar outcomes to males.

The study provides no evidence that females fare better than males following severe TBI, suggesting rather that females may fare worse.