Objective To investigate the expression of serum Hsa_circ_0003928 in patients with diabetic foot ulcer(DFU)and its relationship with the severity and prognosis of disease.Methods 113 DFU patients were selected as the study subjects.According to the severity of infection,19 cases were classified into level 1(no infection),40 cases at level 2(mild infection),20 cases at level 3(moderate infection),and 34 cases at level 4(severe infection).According to the prognosis of DFU patients,they were divided into good prognosis group(GP,n=63)and poor prognosis group(PP,n=50).The baseline data and levels of IL-6,C-RP and Hsa_circ_0003928 were compared among the four groups.Logistic regression was used to analyze the risk factors of poor prognosis in patients with DFU.The receiver operating characteristic(ROC)curve was used to analyze the value ofHsa_circ_0003928,C-RP and IL-6 in predicting the poor prognosis in DFU patients.Results The DFU duration,infection grade 3～4,serum creatinine,uric acid,BUN,C-RP,IL-6 and Hsa_circ_0003928 levels in PP group were significantly higher than those in GP group(P＜0.05 or P＜0.01).Grade 3～4 DFU patients had higher Hsa_circ_0003928 expression than grade 1～2(P＜0.01).Logistic regression analysis showed that long duration of DFU,infection grade 3～4,higher levels of BUN,C-RP,IL-6 and Hsa_circ_0003928 were risk factors for poor prognosis in DFU patients.ROC curve showed that Hsa_circ_0003928 had the greatest AUC(0.882,95％CI 0.819～0.942)in predicting poor prognosis in DFU patients,with sensitivity 87.5％and specificity 85.6％,respectively.Conclusion Elevated Hsa_circ_0003928 is associated with DFU severity and poor prognosis,which has certain predictive value for the prognosis of DFU patients.