No effect of vitamin D supplementation on metabolic parameters but on lipids in patients with type 2 diabetes and chronic kidney disease

Background/Aims: Trials on the effects of cholecalciferol supplementation in type 2 diabetes with chronic kidney disease patients were underexplored. Therefore, the aim of this study was to investigate the effects of two different doses of vitamin D supplementation on serum 25-hydroxyvitamin D [25(OH)D] concentrations and metabolic parameters in vitamin D-deficient Korean diabetes patients with chronic kidney disease. Methods: 92 patients completed this study: the placebo group (A, n = 33), the oral cholecalciferol 1,000 IU/day group (B, n = 34), or the single 200,000 IU injection group (C, n = 25, equivalent to 2,000 IU/day). 52% of the patients had less than 60 mL/min/1.73m2 of glomerular filtration rates. Laboratory test and pulse wave velocity were performed before and after supplementation. Results: After 12 weeks, serum 25(OH)D concentrations of the patients who received vitamin D supplementation were significantly increased (A, -2.4 ± 1.2 ng/mL vs. B, 10.7 ± 1.2 ng/mL vs. C, 14.6 ± 1.7 ng/mL; p < 0.001). In addition, the lipid profiles in the vitamin D injection group (C) showed a significant decrease in triglyceride and a rise in HDL cholesterol. However, the other parameters showed no differences. Conclusions: Our data indicated that two different doses and routes of vitamin D administration significantly and safely increased serum 25(OH)D concentrations in vitamin D-deficient diabetes patients with comorbid chronic kidney disease. In the group that received the higher vitamin D dose, the lipid profiles showed significant improvement, but there were no beneficial effects on other metabolic parameters.