Predictors of in-hospital mortality and 6-month functional outcomes in older adults after moderate to severe traumatic brain injury.

Introduction: Traumatic brain injury (TBI) is the single largest cause of death and disability following injury worldwide. While TBI in older adults is less common, it still contributes to significant morbidity and mortality in this group. Understanding the patient characteristics that result in good and poor outcome after TBI is important in the clinical management and prognosis of older adult TBI patients. This population-based study investigated predictors of mortality and longer term functional outcomes following serious TBI in older adults.

Methods: All older adults (aged>64 years), isolated moderate to severe TBI cases from the population-based Victorian State Trauma Registry for the period July 2005 to June 2007 (inclusive) were extracted for analysis. Demographic, injury event, injury diagnosis, management and comorbid status information were obtained and the outcomes of interest were in-hospital mortality, and the Glasgow Outcome Scale-Extended (GOS-E) score at 6 months post-injury. Multivariate logistic regression analyses were used to identify independent predictors of in-hospital mortality and independent living (GOS-E>4) status at 6 months.

Results: Of the 428 isolated, older adult TBI cases, the majority were the result of a fall (88%), male (55%), and aged>74 years (76%). The in-hospital death rate was 28% and increasing age (p=0.009), decreasing GCS (p<0.001) and injury type (p=0.002) were significant independent predictors of in-hospital mortality. Of the 310 patients who survived to discharge, 65% were successfully followed-up 6 months following injury. There was no difference between patients lost to follow-up and those successfully followed-up with respect to the key population indicators of age, gender, or head injury severity. Younger (<75 years) patients, and those with an SBP on arrival at hospital of 131-150mmHg, were at increased odds of living independently at follow-up. No patients with a GCS<9 had a good 6-month outcome, and most of them died. The survival rate for brainstem injury was also low (21%).

Conclusion: In this population-based study, we found that age, GCS, brainstem injury, and systolic blood pressure were the most important factors in predicting outcome in older adults with an isolated moderate to severe TBI.