Association between vitamin D status and diabetic foot in patients with type 2 diabetes mellitus

AIMS/INTRODUCTION: To assess the association between vitamin D and diabetic foot (DF) in patients with type 2 diabetes mellitus (T2DM), in order to summarize clinical evidence in the prevention and treatment of DF. MATERIALS AND METHODS: Between January 2012 and December 2019, a total of 1,721 hospitalized patients with type 2 diabetes mellitus were continuously enrolled in West China Hospital, Sichuan University, and divided into DF and non‐DF groups according to whether they had DF, and divided into four subgroups according to the admission season. The 25‐OH‐vitamin D levels were compared between groups and subgroups, and independent risk factors discussed for the occurrence of DF. RESULTS: The vitamin D insufficiency and deficiency rate were higher in the DF group (77.51%) than in the non‐DF group (59.2%). The 25‐OH‐vitamin D levels were lower in the DF group (35.80 nmol/L) than in the non‐DF group (45.48 nmol/L) (P < 0.001). Patients with poor glycemic control had lower 25‐OH‐vitamin D levels (P = 0.01). The levels of 25‐OH‐vitamin D were lower in winter and spring. In the same season, the levels of 25‐OH‐vitamin D in patients with DF were still lower (P < 0.001). The 25‐OH‐vitamin D levels of patients with Wagner grades 0 to 5 showed a downward trend (P = 0.114). The 25‐OH‐vitamin D level was independently associated with diabetic foot (P < 0.001, OR = 0.986). CONCLUSIONS: The low serum vitamin D level was significantly associated with a higher prevalence of DF among Chinese patients with type 2 diabetes mellitus. Although vitamin D levels vary seasonally, patients with DF were always at higher risk of having vitamin D insufficiency and deficiency.