Evidence synthesis: Sex and gender effects in health and functional outcomes of traumatic brain injury

Research Objectives: To summarise the evidence on the effect of sex and gender on core traumatic brain injury (TBI) outcomes.

Design: All English language studies from six literature databases that addressed core outcomes in persons with TBI and included sex or gender among the variables hypothesized to be associated with outcome were considered. The results were sorted according to the timing of assessments, injury severity, gender equity ranking of the study’s country of origin, and outcomes studied.

Setting: No restriction to the setting or country of study origin.

Participants: Of 172 articles assessed, 58 studies were selected and included a total of 1,265,955 participants with TBI (male participants comprised 67% across study samples) of all injury severities. All studies were conducted in countries with a very high or high human development index; the gender inequality index of these countries varied.

Interventions: N/A

Main Outcome Measures: Outcomes were organised into the following categories: mortality, structural/physiological, care, medical, psychiatric disorders, sleep-related, cognitive functioning, functional outcome, disability, social participation, work-related, and life satisfaction.

Results: Following data stratification and tabulation of the frequency of significant results for male or female participants’ susceptibility in relation to the studied outcomes, the most common results indicated no difference between male and female patients with TBI across outcome categories, injury severities, and phases post-injury. The next pattern that emerged was that as the gender equality ranking of the study origin improves, differences between male and female participants on health and functional outcomes, across injury severities, start to disappear. Inclusion of social equity parameters in studies reporting on sex and gender effects was limited.

Conclusions: The nonuniform effect of sex and gender on TBI outcomes supports the concept that sex and gender should be studied along with gender equality and social equity parameters in research.

Author(s) Disclosures: This work was supported by a research grant from the Canadian Institutes for Health Research Grant, Institute for Gender and Health (#CGW-126580), and partially by Canada Research Chairs programs.