Correlation between serum 25(OH)D levels and diabetic foot ulcers in elderly patients with type 2 diabetes mellitus.

OBJECTIVE: To explore the correlation between serum 25-hydroxyvitamin D (25(OH)D) levels and diabetic foot ulcers (DFU) in elderly type 2 diabetes mellitus (T2DM) patients. METHODS: Data of 198 T2DM patients treated at Shanghai Traditional Chinese Medicine-Integrated Hospital from June 2021 to June 2023 were retrospectively analysed. Totally 80 patients with DFU were classified into the study group, while the other 118 were the control group. Outcome measures included serum 25(OH)D levels and nutritional status, the relationship between the severity of DFU and serum 25(OH)D levels, lipid-related and glucose-related indicators, and independent influencing factors for the severity of DFU in elderly T2DM patients. RESULTS: The control group demonstrated significantly higher serum 25(OH)D levels compared to the study group (P<0.001), and a lower prevalence of 25(OH)D deficiency (65.25% vs. 86.25%, P=0.001). A strong inverse correlation was observed between Wagner grade and 25(OH)D levels (r=-0.746, P<0.001). The control group presented notably lower total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG) levels than the study group (P<0.001), but a notably higher high-density lipoprotein cholesterol (HDL-C) (P<0.001). Multivariate logistic regression analysis identified diabetes duration (OR: 1.15-9.23, P=0.026) and serum 25(OH)D levels (OR: 0.40-0.85, P=0.005) as independent predictors of DFU severity. CONCLUSION: 25(OH)D deficiency is strongly associated with the risk of DFU. Diabetes duration and serum 25(OH)D levels are independent risk factors for DFU severity in elderly patients with T2DM.