Risk Factors Analysis for 90-Day Mortality of Adult Patients with Mild Traumatic Brain Injury in an Italian Emergency Department.

Purpose : The most prominent risk factors for mortality after mild traumatic brain injury (TBI) have not been established. This study aimed to establish risk factors related to 90-day mortality after a traumatic event. Methods : A retrospective cohort study on adult patients entering the Emergency Department of the University Hospital of Trieste for mild TBI from 1 January 2020 to 31 December 2020 was conducted. Results : The final population was 1221 patients (median age of 78 years). The 90-day mortality rate was 7% (90 patients). In the Cox regression model (likelihood ratio 110.9; p < 2 × 10-16 ), the variables that significantly correlated to 90-day mortality were age (less than 75 years old is a protective factor, HR 0.29 [95%CI 0.16-0.54]; p < 0.001); chronic liver disease (HR 4.59 [95%CI 2.56-8.24], p < 0.001); cognitive impairment (HR 2.76 [95%CI 1.78-4.27], p < 0.001); intracerebral haemorrhage (HR 15.38 [95%CI 6.13-38.63], p < 0.001); and hospitalization (HR 2.56 [95%CI 1.67-3.92], p < 0.001). Cardiovascular disease (47% vs. 11%; p < 0.001) and cognitive impairment (36% vs. 10%; p < 0.001) were more prevalent in patients over 75 years of age than the rest of the population. Conclusions : In our cohort of patients with mild TBI, 90-day mortality was low but not negligible. The risk factors associated with 90-day mortality included age, history of chronic liver disease, and cognitive impairment, as well as evidence of intracerebral hemorrhage and hospitalization. The mortality of the sub-population of older patients was likely to be linked to cardiovascular comorbidities and neurodegenerative diseases.