Risk Factors for Mortality in Severe Fever with Thrombocytopenia Syndrome Patients with Central Nervous System Complications

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is a zoonotic viral hemorrhagic fever caused by the SFTS virus (SFTSV), which is a newly identified tick-borne bunyavirus, recently named Dabie bandavirus. In rural China, SFTSV or Dabie bandavirus is commonly transmitted by Haemaphysalis longicornis, the Asian longhorned tick. In recent years, SFTS has been of great concern due to its high morbidity and mortality. The present study investigated the risk factors for mortality in patients with SFTS complicated by central nervous system involvement. MATERIAL/METHODS: We studied 69 SFTS patients hospitalized between 2013 and 2020. We analyzed the laboratory test results and clinical data through univariate and multivariate regression. RESULTS: Neurological complications occurred in 59 patients in the survival group and 10 in the mortality group. No significant gender difference was found between the 2 groups. No significant difference was found in age, hospitalization duration, or occurrence of encephalitis between the 2 groups. The mean duration of hospitalization and course of the disease in the mortality group were significantly shorter than those in the survival group (P<0.01). The mean values of platelet count, potassium, and sodium in the mortality group were significantly lower, while the mean values of aspartate aminotransferase, lactic dehydrogenase, creatine kinase-MB (CK-MB) and procalcitonin were higher than those in the survival group. Low platelet count and high CK-MB were independent risk factors for mortality in patients. For each unit increase in platelet count, the risk of mortality decreased by 24.2%, and for each unit increase in CK-MB, the probability of mortality increased by 118.6%. CONCLUSIONS: Decreased platelets and increased CK-MB were independent risk factors for mortality in encephalitis patients. SFTS patients with encephalitis should be monitored for changes in these 2 indicators.