Rapid Prognostic Tools in Disaster Medicine: Car and Bilar in Crush Syndrome

Background The aim of this retrospective study was to evaluate the prognostic value of the C-reactive protein-to-albumin ratio (CAR) and the bicarbonate-to-lactate ratio (BILAR) in patients who developed crush syndrome and to determine their role in predicting mortality and clinical outcomes. Materials and methods This study included patients over 18 years of age who were diagnosed with crush syndrome following the February 6, 2023 Kahramanmaraş earthquakes. Demographic, clinical, and laboratory data were analyzed. The CAR was calculated using the formula CRP (mg/L)/Albumin (g/L), while the BILAR was derived as the ratio of HCO₃ (mmol/L) to lactate (mmol/L). The primary endpoint was defined as mortality, and the secondary endpoints included amputation, intensive care unit (ICU) admission, stage 3 acute kidney injury (AKI), and the need for renal replacement therapy. The prognostic impact of CAR and BILAR indices on mortality was assessed using statistical analyses. Results: A total of 231 patients (mean age 36.63 ± 12.35 years, 51.1% female) were included, of whom 18 (7.8%) died. Mortality was significantly associated with elevated levels of BUN, creatinine, potassium, phosphorus, AST, ALT, creatine kinase, lactate, and the CAR index, as well as decreased albumin, calcium, HCO₃⁻, hemoglobin, and BILAR index values (p < 0.05). CAR > 3 and BILAR < 5 demonstrated strong predictive value for mortality based on their AUC scores. ROC analysis revealed that CAR showed moderate-to-good discriminative ability for mortality (AUC = 0.64), stage 3 AKI (AUC = 0.73), ICU admission (AUC = 0.75), amputation (AUC = 0.65), and the need for hemodialysis (AUC = 0.72). According to the Youden index, the optimal CAR cut-off for predicting mortality was 2.37 (sensitivity = 83%, specificity = 44%). Low BILAR values were inversely associated with all endpoints, with BILAR < 5 showing a particularly strong correlation with mortality (p < 0.001). Conclusions: CAR and BILAR are rapid and easily calculated prognostic indices in crush syndrome. Elevated CAR and decreased BILAR values at admission show a strong association with mortality and may provide valuable clinical decision support for early risk stratification and treatment planning in mass-casualty disaster settings.