Dynamic change in cortisol levels associated with severity, progression, and survival of patients with traumatic brain injury

Background: Cortisol levels are elevated in severe traumatic brain injury (TBI) and gradually decrease during patient recovery. Thus, dynamic changes in cortisol levels may serve as a prognostic biomarker of TBI.Aim: This study aimed to examine the relationship between serum cortisol levels and outcomes in TBI patients.Methods: In this prospective case-cohort study, 238 patients with TBI were enrolled. Demographic, clinical, and radiological data were recorded within the first 24 h of hospitalization. Serum cortisol levels were measured using chemiluminescence assay (Immunoassay i1000). The association between cortisol levels and outcome (Glasgow Outcome Scale score) was evaluated at discharge from the hospital and after six months of follow-up. Results: The mean age of the patients was 35.03 +/- 17.68 years and the male: female ratio was 4.3:1. At the time of admission(day-1), cortisol levels in the TBI patients were significantly higher than those on day-7 (9.81 +/- 4.20 mu g/dl versus 23.41 +/- 11.83 mu g/dl; p<0.001). There was a significant relationship between cortisol levels and Glasgow Coma Scale (GCS) (p = 0.018). Moderate head injury (GCS;9-12) was observed in 108(45.4 %) patients and 130(54.6 %) patients with severe head injury (GCS;3-8) at presentation. CGS was significantly associated with the survival of patients with TBI; alive(n = 143) vs. dead (n = 77); p < 0.001. At 6 months follow-up of patients (n = 184), the findings revealed that the Glasgow Outcome Scale (GOS) and GCS score were significantly associated(p = 0.018). One-way ANOVA showed a significant difference in cortisol levels on day-1, day-7 and six months of sampling (p < 0.0001). Based on the GOS E score, the cortisol levels in the unfavorable and favorable groups significantly differed from those in the GOSE groups (p = 0.05). Similarly, cortisol levels were significantly associated with survival in patients with TBI (p = 0.04). With increasing cortisol levels, the GOSE score was poor and at > 50 mu g/dl, no patient has survived.Conclusions: Day 1 and 7 cortisol, correlated with the outcomes at 6 months, had predictive value post-TBI.