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

Abstract Background Although age and trauma-induced coagulopathy (TIC) 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 TIC 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 (AIS) ≥3, and other AIS <3] were selected, and divided into the non-elderly (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, and/or platelet count <120 × 10 9 /L, and/or fibrinogen ≤150 mg/dL) on TBI outcomes [Glasgow Outcome Scale-Extended (GOS-E) scores, in-hospital mortality, and ventilation-free days (VFD)] in both groups using univariate and multivariate models. Further, we conducted an age-based assessment of the impact of coagulopathy on GOS-E using a generalized additive model.Results The multivariate model showed a significant association of age and coagulopathy with lower GOS-E scores, in-hospital mortality, and shorter VFD in the non-elderly 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 age over 65 years old.Conclusions There was a low impact of coagulopathy on functional and survival outcomes in geriatric patients with isolated TBI.