Clinical and laboratory features of Crimean-Congo hemorrhagic fever: predictors of fatality

Summary 

Objective

To determine the predictors of fatality among patients with Crimean-Congo hemorrhagic fever (CCHF) based on epidemiological, clinical, and laboratory findings.

Methods

Among the patients with possible CCHF who were referred to Ankara Numune Education and Research Hospital (ANERH) from the surrounding hospitals between 2003 and 2006, those with IgM antibodies and/or reverse transcriptase-polymerase chain reaction (RT-PCR) results positive for CCHF virus in their blood, and who had received only supportive treatment, were included in the study.

Results

Sixty-nine patients with CCHF were admitted to ANERH from various cities of the northeastern part of the central region and southern parts of the Black Sea region of Turkey. Eleven (15.9%) patients died. Age, gender, days from the appearance of symptoms to admission, and initial complaints except bleeding were similar between fatal and non-fatal cases (p>0.05). Among the clinical findings, ecchymosis (p=0.007), hematemesis (p=0.030), melena (p<0.001), somnolence (p<0.001), and gingival bleeding (p=0.044) were more common among fatal cases. The mean platelet count was 47.569×10⁹/l in non-fatal cases and 12.636×10⁹/l in fatal cases (p=0.003). Among the fatal cases, the mean prothrombin time (PT; 18.4s vs. 13.4s; p<0.001) and the mean activated partial thromboplastin time (aPTT; 69.4s vs. 42.7s; p=0.001) were longer, and the mean alanine aminotransferase (ALT; 1688 vs. 293; p<0.001), mean aspartate aminotransferase (AST; 3028 vs. 634; p<0.001), mean lactate dehydrogenase (LDH; 4245 vs. 1141; p<0.001), mean creatine phosphokinase (CPK; 3016 vs. 851; p=0.004) levels and the mean international normalized ratio (INR; 1.38 vs. 1.1; p<0.001) were higher. In a Cox proportional hazards model, thrombocytopenia of ≤20×10⁹/l (hazard rate (HR) 9.67; 95% confidence interval (CI) 1.16–80.68; p=0.036), a prolonged aPTT ≥60s (HR 11.62; 95% CI 2.40–56.27; p=0.002), existence of melena (HR 6.39; 95% CI 1.64–24.93; p=0.008), and somnolence (HR 6.30; 95% CI 1.80–22.09; p=0.004) were independently associated with mortality.

Conclusions

Thrombocytopenia of ≤20×10⁹/l, a prolonged aPTT ≥60s, the existence of melena, and somnolence were independent predictors of fatality.

Keywords: Crimean-Congo hemorrhagic fever, Fatality