Low Thoracic Muscle Mass: A Novel Indicator of Poor Prognosis in Patients With Severe Fever With Thrombocytopenia Syndrome

Background Severe fever with thrombocytopenia syndrome (SFTS) poses a serious threat to public health due to its high mortality. Low thoracic muscle mass predicts poor clinical outcomes in many diseases, but its significance in SFTS remains unclear. Methods This retrospective study involved 210 SFTS patients admitted to the First Affiliated Hospital of Anhui Medical University from 2020 to 2023. All subjects underwent chest computed tomography (CT) examination. Skeletal muscle index (SMI) was measured by CT images at the level of the twelfth thoracic vertebra (T12). The clinical data of patients from the survival and non‐survival groups were compared, and the prognostic value of T12‐SMI in SFTS patients was evaluated through least absolute shrinkage and selection operator regression and univariate and multivariate Cox regression. Results Patients in the non‐survival group had a lower SMI. Receiver operating characteristic analysis indicated that SMI may predict adverse outcomes in patients with SFTS. Multivariate Cox regression analysis demonstrated that SMI was independently connected to negative outcomes of SFTS. T12‐SMI was correlated with albumin and creatinine. Conclusion Low SMI is associated with adverse outcomes in patients with SFTS. SMI may serve as a reliable prognostic marker for SFTS in clinical settings.