Bilirubinemia Significantly Affects Clinical Outcomes in Patients with Severe Traumatic Brain Injury (TBI)

Objective: Total bilirubin levels (TBLs) may serve as biomarkers of physiological stress or organ dysfunction in critically ill patients. We aimed to evaluate the association between TBLs and clinical outcomes in patients with severe traumatic brain injury (TBI). Methods: This is a single-center, retrospective study of patients with severe TBI treated between 1 January 2020 and 31 December 2023. Patients were identified using the Glasgow Coma Scale (GCS ≤8) and the Abbreviated Injury Scale (AIS ≥3). TBLs were collected at five clinical time points: hospital admission, ICU admission, ICU discharge, hospital discharge, and at death. Regression models were used to assess associations between TBLs and key outcomes, including emergency department (ED) length of stay (LOS), hospital LOS, ICU LOS, ventilator days, and in-hospital mortality. Results: Elevated TBLs were most common at hospital admission (10.7%) and declined progressively through the hospital stay. In multivariable analysis, higher TBLs at hospital admission and death were significantly associated with in-hospital mortality (OR 1.02, p<0.05 and OR 1.05, p<0.001, respectively). No significant associations were found between bilirubin levels and LOS or ventilator days in adjusted models. Multivariate analyses analyzing the effect of bilirubin levels on various clinical outcomes revealed significant associations among a variety of primary predictors (including total bilirubin level, race, severity score, and drug screen). Conclusions: Elevated TBLs at admission and at the time of death are associated with increased mortality in patients with severe TBI. Bilirubin may hold prognostic value when measured at specific clinical points.