Abstract: Objective To explore the effect of using a multi-index combined evaluation based on mean platelet volume/lymphocyte ratio (MPVLR) in the progression of fever with thrombocytopenia syndrome (SFTS) patients, provide scientific guidance for the diagnosis and treatment of SFTS patients. Method A retrospective of a total of 150 patients with SFTS from January 2017 to October 2024 admitted to Nanjing Lishui District People's Hospital were selected as the SFTS group. 150 patients with fever accompanied by normal platelets during the same period were selected as the fever accompanied by normal platelets group, 150 patients without fever accompanied by thrombocytopenia were selected as the non fever accompanied by thrombocytopenia group, and 150 healthy individuals who underwent physical examination during the same period were selected as the control group. The levels of MPVLR, interleukin-11 (IL-11), C reactive protein (CRP), mean platelet volume (MPV), lymphocyte (LYM), neutrophil (NEUT), white blood cell (WBC), lactate dehydrogenase (LDH), creatine kinase isoenzyme (CK-MB), alanine aminotransferase (ALT), and aspartate amino transferase (AST) of patients with different degrees of illness in the four groups were compared, and univariate and multivariate Logistic regression analyses were conducted. Receiver operating characteristic (ROC) curves were plotted to clarify the predictive value of multi-index joint evaluation for the progression of SFTS. Result There were statistically significant differences in the levels of MPVLR, IL-11, and CRP among the four groups (P<0.05). Among 150 SFTS patients, a total of 88 cases (58.67%) were classified as mild symptoms, and 62 cases (41.33%) were classified as severe symptoms. The results of one-way factor analysis showed that MPVLR, IL-11, CRP, LDH, CK-MB, ALT and AST levels in severe group were higher than those in mild group (P<0.05). The results of multiple Logistic regression analysis showed that MPVLR (OR=2.639, P<0.05), IL-11 (OR=4.127, P<0.05), and CRP (OR=2.693, P<0.05) were independent factors affecting the progression of SFTS. The ROC curve showed that the area under the curve of MPVLR, IL-11 and CRP combined to predict the progression of SFTS was 0.856, which was higher than that of MPVLR (area under the curve was 0.823), IL-11 (area under the curve was 0.752) and CRP (area under the curve was 0.745) alone (P<0.05). Conclusion The expression levels of MPVLR, IL-11, and CRP are relatively high in SFTS patients, especially in severe SFTS patients. The combined evaluation of multiple indicators has high clinical value in predicting the progression of SFTS and can serve as an important basis for disease diagnosis and treatment planning.

Key words: Severe fever with thrombocytopenia syndrome, Disease progression, Mean platelet volume/lymphocyte ratio, Interleukin-11, C reactive protein