Can Serum Ferritin Level Predict Disease Severity in Patients with Crimean-Congo Hemorrhagic Fever?

Objective: Crimean-Congo hemorrhagic fever (CCHF) is an acute viral disease. Several factors have already been suggested to explain the pathogenesis as well as predict the disease severity. In our study we aim to investigate the role of serum ferritin level as a possible predicting factor of disease severity in these patients. Materials and Methods: We evaluated all patients with laboratory confirmed diagnosis of CCHF who were admitted to Boo-Ali Hospital of Zahedan from May 2011 to June 2012. Confirmation of the disease determined using the presence of anti-CCHFV IgM in the serum by enzyme-linked immunosorbent assay (ELISA) or by polymerase chain reaction(PCR). After ethical approval, patients were categorized into two groups of mild and severe disease according to disseminated intravascular coagulation (DIC) severity using the scoring system of International Society on Thrombosis and Hemostasis (ISTH). Serum ferritin levels were evaluated and compared between these two groups. Receiver operating characteristic (ROC) curve analysis was performed to assess the optimal cutoff value of serum ferritin for predicting the disease severity. Results: A total of 42 patients (36 men, 6 women, age range: 17-78 years) were included in this study, of whom 38% had Persian and 62% had Baloch ethnicity. According to DIC severity score, 54.7% of the patients had severe disease and 45.3% had mild disease. The area under the ROC curve was 0.896 and 95% CI was 0.801-0.991 (p< 0.0001). A cut-off point of 1060 ng/ dL, had a sensitivity of 78.9%, a specificity of 87%, a positive predictive value of 6% and a negative predictive value of 100%. Positive and negative likelihood ratios for this serum ferritin level were 6.05 and 0.24, respectively. Conclusion: Increased serum ferritin level has a significant positive correlation with disease severity in patients with CCHF and can evaluate the prognosis of these patients with a high sensitivity and specificity.