The evaluation of clinical laboratory features and mortality risk factors in patients with crimean-congo hemorrhagic fever

Introduction and Purpose Crimean-Congo Hemorrhagic Fever (CCHF) is a zoonotic disease transmitted to humans through bites from infected ticks or contact with the blood and tissues of infected animals. CCHF, which is widespread globally and in our country and is expected to continue to be prevalent in the future. It is a multisystemic disease that can affect multiple organ systems and cause significant morbidity and mortality. The information about the pathogenesis and treatment of the disease is limited in the literature. Early diagnosis and treatment of CCHF are crucial for reducing morbidity and mortality. Identifying factors that may influence the prognosis of the disease can guide early diagnosis and treatment, especially in patients at risk of severe clinical outcomes. In our study, we aimed to evaluate the clinical and laboratory findings of CCHF cases to identify risk factors associated with mortality, guided by findings in the literature. We believe that the data obtained in this study will help reduce mortality and morbidity in patients with CCHF. Method The study included 234 adult patients with the diagnose of CCHF who were admitted to Yozgat Bozok University Research and Practice Hospital, Department of Infectious Diseases and Clinical Microbiology, from April 19, 2020, to October 1, 2023. Blood samples were sent to the reference laboratory of the Turkish Public Health Institute of the Turkish Ministry of Health for definitive diagnosis in patients suspected of having CCHF. CCHF RNA was tested using real-time PCR in the blood samples. The patients' age, gender, place of residence, symptoms, duration of symptoms, physical examination findings, laboratory tests at the time of admission were evaluated. Patient follow-up and treatment were arranged according to daily physical examination and laboratory tests, and the data were recorded in the follow-up form. These data were analyzed to identify risk factors associated with morbidity and mortality. Statistical analyses were performed using the STATA 11.0 (College Station, Texas, USA) software. Results Most of the patients diagnosed with CCHF were from rural areas (59%) and the male gender (68.4%) was more prevalent. In the deceased patient group, the average age and the number of chronic diseases were higher, while both total hospitalization and ward stay durations were shorter (p<0.001). Chronic diseases such as diabetes mellitus (DM) and hypertension (HT) were more frequent in deceased patients (p<0.05). The social status and habits of the patients were not associated with mortality. The BRh (+) blood group was more common among deceased patients (p=0.007). Among admission complaints; diarrhoea, rash and jaundice, tachycardia, hypotension and hypertension, as well as physical examination findings like maculopapular rash, hepatomegaly, splenomegaly, jaundice, abdominal distension, pleural effusion, somnolence and agitation were more common (p<0.05) in deceased patients. Bleeding was significantly more frequent in deceased patients (p<0.001). Especially pulmonary haemorrhage, GI bleeding, bleeding into body cavities, petechiae, ecchymosis, haematoma, melena, haematuria and haemoptysis were more associated with mortality (p<0.05). The use of fresh frozen plasma, pooled platelets, cryoprecipitate, red blood cell suspension, tranexamic acid, and corticosteroids was more frequent in deceased patients, paralleling the frequency of bleeding (p<0.05). Among hematological values in deceased patients, higher and lower WBC counts, lower lymphocyte, hematocrit (HCT), hemoglobin (HGB), and platelet (PLT) counts, and higher levels of biochemical values such as AST, ALT, AST/ALT ratio, LDH, urea, creatinine, bilirubins, amylase, CRP, and GGT were observed. Additionally, the NEU/LYMPH ratio was higher and the PLT/LYMPH ratio was lower in deceased patients (p<0.05). Coagulation time was also longer in deceased patients (p<0.05). Conclusion CCHF is a disease with high mortality. When evaluating patients, medical history, clinical findings, physical examination and laboratory tests should be taken into consideration. Differential diagnoses and co-infections should also be considered during patient evaluation. Low fibrinogen, thrombocytopenia, lung bleeding, GI bleeding, agitation and the presence of DM were were identified as independent risk factors for mortality in deceased patients. Close monitoring, early diagnosis, and supportive treatment for patients with these risk factors can significantly reduce mortality risk, even though the exact pathogenesis of the disease is not fully understood. Keywords: Crimean-Congo Hemorrhagic Fever, mortality, risk factors