Zhikai Qian, Yongyang Sun, Jinyu Bai, Bo Jiang, Jiaju Zhao

Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Soochow, 215004, People’s Republic of China

Correspondence: Jiaju Zhao, Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Soochow, 215004, People’s Republic of China, Tel/Fax +86-512-67784127, Email zpj1985@163.com

Background: Diabetic foot amputation represents the severe complication of patients with diabetic foot ulcers (DFU), with worsened clinical outcomes concomitant with 25-hydroxyvitamin D [25-(OH)D] deficiency. This study aimed to investigate the value of 25-(OH)D deficiency and its association with minor lower limb amputation in Chinese patients with DFU in type 2 diabetes mellitus (T2DM).
Methods: Ninety-one T2DM patients with DFU undergoing minor amputation (surgical group), 94 T2DM patients without DFU (diabetic control group), and 40 healthy controls were enrolled in the study finally. Serum 25-(OH)D levels were measured by stable isotope dilution-high performance liquid chromatography-tandem mass spectrometry. Patients in the surgical group underwent pathogen detection.
Results: The overall incidence of 25-(OH)D deficiency was 73.0%. Amputation group exhibited significantly higher prevalence versus control group (85.7% vs 60.6%, P< 0.001). The levels of serum 25-(OH)D in the minor amputation group were significantly lower than the T2DM group [10.71 (8.2,16.7) vs 18.8 (15.0, 23.9) ng/mL, P< 0.001]. Compared with the control group, amputation group showed lower 25-(OH)D, calcium, albumin and higher WBC, platelet, inflammatory markers (all P< 0.001). Minor amputation subgroups showed that 25-(OH)D deficiency associated with elevated WBC (P=0.002), PLT (P=0.011), D-dimer (P=0.041), HbA1c (P=0.033), SII (P=0.023). While low expression of 25-(OH)D group had higher WBC (P=0.016), D-dimer (P=0.004), SIRI (P=0.042), lower albumin (P=0.009) vs high expression group. ROC analysis confirmed 25-(OH)D as superior amputation predictor (AUC=0.798, 95% CI 0.734– 0.861) compared to inflammatory markers. Multivariate regression identified deficiency as independent amputation risk factor. Polymicrobial infections (26.4%) correlated with lower 25-(OH)D (P=0.003), with Gram-negative (52.4%) and Gram-positive bacteria (47.6%) among bacterial infections.
Conclusion: 25-(OH)D deficiency occurs in 85.7% of patients with minor amputation in DFU, and the levels of 25-(OH)D decreased. 25-(OH)D deficiency is a vital risk factor for minor amputation and measures should be taken to prevent 25-(OH)D deficiency in T2DM patients with DFU.

Keywords: 25-(OH)D deficiency, diabetic foot ulcers, minor amputation, type 2 diabetes mellitus