The effectiveness of routine laboratory findings in determining disease severity in patients with Crimean-Congo hemorrhagic fever: severity prediction criteria

Abstract

Background: Crimean-Congo hemorrhagic fever (CCHF) is a potentially fatal disease caused by a tick-borne virus from the Bunyaviridae family.

Objectives: To determine the predictive criteria for severity among patients with CCHF based on clinical and laboratory findings.

Study design: This retrospective study was conducted on patients with CCHF and hospitalized between June 2004 and August 2008 at Karadeniz Technical University, Turkey. Demographic characteristics, clinical findings and laboratory tests on admission of all patients with CCHF were investigated.

Results: A total of 152 patients with confirmed CCHF were investigated. Sixty-three (41.4%) of these patients were in the severe group. Laboratory findings using the ROC curve method and optimum diagnostic cut-off points for specific laboratory parameters in the severe group were; PLT: 90,000, Hb: 13.5 g/dL, PT: 13.1s, aPTT: 34 s, INR: 1, AST: 117U/L, ALT: 71U/L, AST/ALT: 1.62, LDH: 508 U/L, CK: 267 U/L and CRP: 0.59 mg/dL. At multivariable analysis, the risk for a severe clinical course in CCHF patients increased 2.59 and 3.93 times in the presence of platelet count and Hb below cut-off values, whereas the same risk increased 2.95, 2.92 and 3.47 times when the results for INR, AST and CRP, respectively, were above the predetermined cut-off values.

Conclusions: A number of laboratory findings that can easily be measured at routine examination of patients hospitalized with a suspicion of CCHF are valuable and sensitive predictors. These parameters will contribute considerably to the design, practice and management of supportive treatment, blood and blood products replacement and intensive care services.