Serum Caspase-1 as an Independent Prognostic Factor in Traumatic Brain Injured Patients

Background The objectives of this study were to assess the association between serum caspase 1 levels and known clinical and radiological prognostic factors and determine whether caspase 1was a more powerful predictor of outcome after traumatic brain injury (TBI) than clinical indices alone, to determine the association between the serum levels of caspase 1 and the 6-month outcome, and to evaluate if there is any association between caspase 1 with clinical and radiological variables. Methods This prospective and observational study was conducted in a university hospital and included patients with TBI who required hospital admission. Serum samples were collected at hospital admission and 24 h after TBI. Caspase 1 levels were determined by enzyme-linked immunosorbent assay. Receiver operating characteristic curves were obtained to test the potential of caspase 1 to predict mortality (Glasgow Outcome Scale Extended score of 1) and unfavorable outcome (Glasgow Outcome Scale Extended scores of 1–4). Multivariate logistic regression was used to assess the effect of serum caspase 1 levels, adjusted by known clinical and radiological prognostic indices, on the outcome. Results One hundred thirty-two patients and 33 healthy controls were included. We obtained 6-month outcome in 118 patients. On admission, the mean serum levels of caspase 1 were higher in patients with TBI compared with controls (157.9 vs. 108.5 pg/mL; p < 0.05) but not at 24 h after TBI. Serum caspase 1 levels on admission were higher in patients with unfavorable outcomes (189.5 vs. 144.1 pg/mL; p = 0.009). Similarly, serum caspase 1 levels on admission were higher in patients who died vs. patients who survived (213.6 vs. 146.8 pg/mL; p = 0.03). A logistic regression model showed that the serum caspase 1 level on admission was an independent predictor of 6-month unfavorable outcomes (odds ratio 1.05; 95% confidence interval 1–1.11; p = 0.05). Caspase 1 levels were higher in patients with severe TBI compared with those with moderate TBI, those with mild TBI, and healthy controls ( p < 0.001). We did not find any correlation between caspase 1 and the radiological variables studied. Conclusions In this cohort of patients with TBI, we show that serum caspase 1 protein levels on admission are an independent prognostic factor after TBI. Serum caspase 1 levels on admission are higher in patients who will present unfavorable outcomes 6 months after TBI. Caspase 1 levels on admission are associated with the injury severity determined by the Glasgow Coma Scale.