Role of vitamin D3 in lipid metabolism and chronic pain in advanced diabetic kidney disease and its rehabilitation

Recently, the prevalence of type 2 diabetes has substantially increased, largely due to improvements in economic conditions and lifestyle changes. Type 2 diabetes disrupts carbohydrate and lipid metabolism, leading to damage to multiple organs, including the kidneys. Diabetic kidney disease (DKD) is a chronic microvascular complication of diabetes that can result in end-stage renal disease. This study aimed to elucidate the biochemical factors involved in the diagnosis of DKD and their interrelationships for delaying the progression of DKD. The plasma levels of vitamin D, inflammatory factors, blood lipids, and complement were analyzed in patients with DKD. Furthermore, the risk factors and their relationship in patients with DKD were examined to provide clinical evidence for delaying the progression of DKD. Patients were divided into three groups according to urinary albumin-creatinine ratio (UACR). Group 1 comprised individuals with type 2 diabetes and normal microalbuminuria (stage A1), group 2 included those with type 2 diabetes and microalbuminuria (stage A2), and group 3 consisted of individuals with type 2 diabetes and macroalbuminuria (stage A3). A total of 112 patients with type 2 diabetes who were hospitalized in the endocrinology department between July 2020 and December 2023 were selected in the study. The patients were divided into three groups based on their albuminuria status: the normal albuminuria group (A1, n = 53; control group), the microalbuminuria group (A2, n = 28), and the macroalbuminuria group (A3, n = 31) groups. The fasting levels of vitamin D 3 , blood lipids, UACR, inflammatory factors, complement, and glucose metabolism indices were measured and subjected to statistical analysis. Compared with the A1 group (with normal microalbuminuria), increased serum low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), erythrocyte sedimentation rate (ESR), visual analog scale (VAS) scores ( P < 0.001, P = 0.016, P < 0.001, and P < 0.001, respectively), and decreased high-density lipoprotein cholesterol (HDL-C) and vitamin D 3 levels ( P = 0.046 and P < 0.001, respectively) were found in the A2 and A3 groups. The UACR values in groups A2 and A3 were inversely proportional to serum vitamin D 3 levels ( P < 0.001) and positively proportional to serum TG, LDL-C, and VAS scores ( P = 0.003, P = 0.015, and P = 0.005, respectively). A negative correlation was observed between vitamin D 3 and LDL-C levels ( P = 0.003). Further logistic regression analysis demonstrated that a decline in vitamin D 3 and elevations in LDL-C and TG levels were independent risk factors for DKD. The areas under the curve of serum vitamin D 3 , LDL-C, and TG for predicting DKD with macroproteinuria were 0.79, 0.695, and 0.632, respectively. The severity, pain, and lipid metabolism of patients with DKD are associated with vitamin D 3 levels. Serum vitamin D3 levels were identified as a highly predictive factor for the development of DKD with macroproteinuria.