Traumatic brain injury: Association between the Glasgow Coma Scale score and intensive care unit mortality

Traumatic brain injury (TBI) prevalence in Botswana is high and this, coupled with a small population, may reduce productivity. There is no previous study in Botswana on the association between mortality from TBI and the Glasgow Coma Scale (GCS) score although global literature supports its existence.

Our primary aim was to determine the association between the initial GCS score and the time to mortality of adults admitted with TBI at the Princess Marina Hospital, Gaborone, Botswana, between 2014 and 2019. Secondary aims were to assess the risk factors associated with time to mortality and to estimate the mortality rate from TBI.

This was a retrospective cohort design, medical record census conducted from 1 January 2014 to 31 December 2019.

In total, 137 participants fulfilled the inclusion criteria, and the majority, 114 (83.2%), were male with a mean age of 34.5 years. The initial GCS score and time to mortality were associated (adjusted hazard ratio (aHR) 0.69; 95% confidence interval (CI) 0.508 - 0.947). Other factors associated with time to mortality included constricted pupil (aHR 0.12; 95% CI 0.044 - 0.344), temperature (aHR 0.82; 95% CI 0.727 - 0.929), and subdural haematoma (aHR 3.41; 95% CI 1.819 - 6.517). Most cases of TBI (74 (54%)) were due to road traffic accidents. The number of deaths was 48 (35% (95% CI 27.1% - 43.6%)), entirely due to severe TBI.

The study confirmed significant association between GCS and mortality. Males were mainly involved in TBI. These findings lack external validity because of the small sample size, and therefore a larger multicentre study is required for validation.

This study informs the relevant stakeholders in Botswana about sociodemographics, clinical characteristics, management and outcomes of patients admitted to the ICU with severe TBI on the backdrop of scarce ICU resources. It provides a basis for a larger study to inform its external validation.