Abstract:Objective To explore the correlations of plasma mitochondrial DNA（mtDNA）, soluble myeloid cell triggering receptor - 1（sTREM-1）levels with the severity of infection and inflammatory indicators in patients with diabetic foot ulcers（DFU）, in order to reveal their potential value in the assessment of infection and inflammatory status of DFU. Methods A total of 186 DFU patients admitted to Putuo Hospital, Shanghai University of Traditional Chinese Medicine from January 2022 to December 2024 were selected. They were divided into mild-moderate group（135 cases）and severe group（51 cases）according to the severity of disease infection. The routine clinical data and inflammatory indicators of the patients were collected, and the levels of plasma mtDNA and sTREM-1 were detected. Spearman rank correlation analysis was used to evaluate the correlations of plasma mtDNA, sTREM-1 levels with Infectious Diseases Society of America（IDSA）/ International Working Group on Diabetic Foot（IWGDF）classification, C-reactive protein（CRP）, procalcitonin（PCT）, etc. Based on the follow-up results three months after discharge, patients were divided into good prognosis group（121 cases）and poor prognosis group（65 cases）. Multivariable logistic regression analysis was used to analyze the influencing factors of the prognosis of DFU patients. The value of plasma mtDNA and sTREM-1 levels in evaluating the short-term prognosis of DFU patients was analyzed using the receiver operating characteristic（ROC）curve. Results The fasting blood glucose（FPG）, glycosylated hemoglobin（HbA_1C）, CRP, PCT, white blood cell count（WBC）, and neutrophil percentage（NEU%）of patients in the severe group were higher than those in the mild-moderate group（P＜0.05）.The levels of plasma mtDNA and sTREM-1 in the severe group were higher than those in the mild-moderate group［2.20±0.68 vs 1.51±0.49, t=7.658, P＜0.01；（189.16±63.25）pg/mL vs（122.49±30.04）pg/mL, t=9.712, P＜0.01］. The plasma mtDNA and sTREM-1 levels of diabetic foot ulcer patients were positively correlated with the severity of disease infection, CRP, PCT, WBC, and NEU%（P＜0.05）. The proportion of patients with peripheral vascular lesions, the proportion of severe disease infections, as well as the levels of FPG, HbA_1C, CRP, PCT, WBC, NEU%, mtDNA, and sTREM-1 were all higher in the poor prognosis group compared to the good prognosis group（P＜0.05）. Peripheral vascular lesions, severe disease infection, elevated CRP, PCT, NEU%, mtDNA, and sTREM-1 levels were risk factors for poor prognosis of DFU patients（P＜0.05）.The area under the curve of plasma mtDNA, sTREM-1 levels, and the combination of the two indicators in evaluating the short-term poor prognosis of DFU patients were 0.816, 0.814, and 0.898, respectively. Conclusion Plasma mtDNA and sTREM-1levels are closely related to the severity of infection and systemic inflammatory status in DFU, and the combined detection of these two indicators has potential predictive value for the short-term poor prognosis of DFU patients.