Background: Crimean-Congo hemorrhagic fever (CCHF) is an emerging infectious disease that has epidemic and pandemic potential and causes mortality. Predicting the outcome of the disease is important to guide the management of patients and prevent mortality. Materials and Methods: This study aimed to investigate hemogram parameters and hemogram-derived ratios for predicting mortality in 207 patients with CCHF (survivors = 177, nonsurvivors = 30). Results: Compared with the survivor group, the nonsurvivor group had higher neutrophils, neutrophil-to-lymphocyte ratio (NLR), derived NLR (d-NLR), and aspartate aminotransferase (AST), AST-to-lymphocyte ratio index (ALRI) on admission and third day of hospitalization. Higher white blood cells (WBCs), lower platelet-to-lymphocyte ratio on admission, and lower lymphocytes, and monocytes on the third day were found in the nonsurvivor group. Evaluating the change of admission and the third day of laboratory values, a downward trend in neutrophils, NLR, d-NLR, ALRI, and an upward trend in WBCs were found statistically significant in the survivor group. These dynamic changes were not found in the nonsurvivor group. AST (third day) and ALRI (third day) had the highest area under the curve (AUC) in the receiver operating characteristic analysis (0.939 and 0.934, respectively; p-value is <0.0001 for all). The NLR on the third day than on admission had a higher AUC, the optimal cutoff value was 1.44, which resulted in a sensitivity of 93.33 and a specificity of 40.34 (AUC: 0.790, p < 0.0001). The d-NLR on the third day had a higher AUC (with a sensitivity of 81.48 and a specificity of 67.43) than on admission (0.781 and 0.669, respectively). Conclusion: CCHF is a common vector-borne disease and mortality rates are high. This study revealed that NLR, d-NLR, and ALRI can be used as biomarkers to predict mortality. Patients who survived had better improvement in hemogram parameters and ratios. Therefore, patients who do not show this improvement should be followed more closely.
Keywords: AST-to-lymphocyte ratio index; Crimean-Congo hemorrhagic fever; d-NLR; mortality; neutrophil-to-lymphocyte ratio; vector-borne disease.