Age-related differences in the impact of coagulopathy in patients with isolated traumatic brain injury: An observational cohort study

BACKGROUND Although age and coagulopathy are well-known predictors of poor outcome after traumatic brain injury (TBI), the interaction effect of these two predictors remains unclear. OBJECTIVES We assessed age-related differences in the impact of coagulopathy on the outcome following isolated TBI. METHODS We conducted a retrospective observational study in two tertiary emergency critical care medical centers in Japan from 2013 to 2018. A total of 1036 patients with isolated TBI (head Abbreviated Injury Scale >= 3 and other Abbreviated Injury Scale < 3) were selected and divided into the nonelderly (n = 501, 16-64 years) and elderly group (n = 535, age >= 65 years). We further evaluated the impact of coagulopathy (international normalized ratio, >1.2) on the outcomes (Glasgow Outcome Scale-Extended [GOS-E] scores, in-hospital mortality, and ventilation-free days) in both groups using univariate and multivariate models. Further, we conducted an age-based assessment of the impact of TBI-associated coagulopathy on GOS-E using a generalized additive model. RESULTS The multivariate model showed a significant association of age and TBI-associated coagulopathy with lower GOS-E scores, in-hospital mortality, and shorter ventilation-free days in the nonelderly group; however, significant impact of coagulopathy was not observed for all the outcomes in the elderly group. There was a decrease in the correlation degree between coagulopathy and GOS-E scores decreased with those older than 65 years. CONCLUSION There was a low impact of coagulopathy on functional and survival outcomes in geriatric patients with isolated TBI.