Li H, et al. - In a large population of patients in an endemic area, authors ascertained the clinical characteristics of severe fever with thrombocytopenia syndrome (SFTS). The necessity of continued surveillance is underscored by the changing epidemiological features and high case fatality rate (CFR) of SFTS. By monitoring clinical and laboratory data, fatal outcomes can be predicted early. Findings suggested an early application of ribavirin, with best results achieved before the viral load reaches 1×10 6 copies per mL.

Methods

• Researchers conducted a prospective observational study and collected data on patients admitted with laboratory-diagnosed SFTS to the People's Liberation Army Hospital in Xinyang, Henan Province, China.
• They collected the demographic, clinical, laboratory, and treatment data for each patient, and patients were followed up within 2 weeks after discharge or discontinuation of treatment.
• They assessed the correlation between each demographic, clinical, and laboratory variable with a fatal outcome.
• They designed a clinical scoring model for the early prediction of a fatal outcome and analyzed the effect of treatment on outcome.

Results

• As per findings, 2,096 patients with laboratory-confirmed SFTS were admitted between April 1, 2011 and October 31, 2017.
• Results demonstrated the mean age at admission to be 61.4 years (SD 12.2) and 1,239 (59%) patients were female.
• They noted the case fatality rate (CFR) to be 16.2% (95% CI 14.6–17.8).
• Data suggested an association of a higher risk with being male (unadjusted odds ratio [OR] 1.45, 95% CI 1.15–1.83; p=0.002), older age (for a 10-year increase, unadjusted OR 1.82, 95% CI 1.62–2.04; p < 0.0001), longer delay in admission (for every extra day taken before admission to hospital, unadjusted OR 1.18, 1.12–1.24; p < 0.0001), presence of diarrhea (adjusted OR 1.44, 1.12–1.87; p=0.005) or dyspnea (adjusted OR 8.35, 5.97–11.69; p < 0.0001), and development of hemorrhagic signs (adjusted OR 2.79, 95% CI 2.18–3.57; p < 0.0001) or neurological symptoms (adjusted OR 30.26, 21.39–42.81; p < 0.0001).
• They combined the laboratory variables that were correlated to death, which included abnormal concentrations of lactate dehydrogenase, aspartate aminotransferase, and blood urea nitrogen, and abnormal neutrophil percentage, which together with age and neurological symptoms were combined in the clinical scoring system.
• In order to predict risk of death for patients who were evaluated within 6 days after symptom onset, a total score of more than 8 was the optimal threshold (area under the curve 0.879, 95% CI 0.855–0.902).
• A strong predictor of fatal outcome for all participants was viremia (all p < 0.0001).
• Experts noted the efficacy of ribavirin therapy in reducing CFR from 6.25% (15 of 240 participants) to 1.16% (two of 173 participants), but only in patients with a viral load below 1×10 6 copies per mL (hazard ratio 9.72, 95% CI 1.30–72.87; p=0.027).