Abstract
BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is a zoonotic infectious disease with high mortality, and hemophagocytic lymphohistiocytosis (HLH) is one of the rare fatal complications of SFTS. Early prediction of the occurrence of HLH and the identification of prognostic factors in SFTS patients with HLH are crucial for effective clinical management. METHODS: Univariate and multivariate logistic regression were used to analyze the demographic characteristics, clinical manifestations at admission and laboratory parameters of 272 SFTS patients. The ROC curve was used to calculate the optimal critical value of each index based on the survival outcomes of patients, and the kinetic characteristics of laboratory markers predicting the prognosis of patients with HLH were analyzed. RESULTS: Decreased platelet count, reduced ALT/AST ratio, elevated LDH, and increased DD were identified as independent risk factors for HLH in SFTS patients. Age, fibrinogen (FIB), and procalcitonin (PCT) were independent risk factors for mortality in SFTS patients with HLH (P < 0.05). The combination of these three factors can effectively predict patient prognosis (AUC = 0.903). Patients aged ≥64 years, with FIB ≤ 2.23 g/L, and PCT ≥ 0.9 ng/ml exhibited higher mortality rates. The dynamic characteristics of PCT and FIB levels significantly differed between the survival and death groups in SFTS patients with HLH. CONCLUSION: Early laboratory indicators can timely identify HLH complications in SFTS patients. Close monitoring of elderly patients and regular assessment of PCT and FIB levels can effectively reduce mortality.