CRP and vitamin D deficiency: Compared with the NDFO group, the duration of diabetes, the duration of foot ulcer, Wagner grade, infection severity, the proportion of foot ulcer recurrence, the proportion of drug-resistant bacteria detected in the wound, the proportion of vitamin D deficiency, FPG, HbA1c, CRP, WBC, ESR, P-IL-6, and T-IL-6 in the DFO group were significantly increased (P < 0.05).