Nephroprotective potential of vitamin D in patients with diabetic nephropathy

The increase in the number of patients with diabetic nephropathy and the low effectiveness of standard nephroprotective therapy dictates the need to find new, more effective methods of treatment for this group of patients.

Objective. To study the nephroprotective properties of vitamin D in patients with diabetic nephropathy.

Materials and methods. A questionnaire and study of general blood count, general urinalysis, levels of 25-hydroxyvitamin D, creatinine, urea, total protein, glucose, glycated hemoglobin, total calcium, parathyroid hormone, interleukin (IL)-6, -8 and homocysteine were conducted in the blood of 200 patients with diabetes mellitus (DM) and chronic kidney disease (CKD) and 40 apparently healthy individuals aged 18 to 89 years who signed informed voluntary consent. All patients were divided into three study groups: main group – patients with DM and CKD who received vitamin D therapy; comparison group – patients with DM and CKD who did not receive vitamin D therapy; control group – healthy individuals.

Results. All patients suffering from DM, regardless of the duration of the disease, showed signs of CKD. The level of vitamin D in the blood was also reduced in all patients. A direct and strong correlation between the level of vitamin D and the glomerular filtration rate (GFR) indicator and an inverse strong correlation with the concentration of creatinine in the blood of the studied patients have been proven. The positive effect of vitamin D on parameters of parathyroid hormone, IL-6, -8 and homocysteine has been reliably established.

Conclusion. Prescribing the optimal dosage of vitamin D to patients with diabetic nephropathy for 6–12 months helps to reduce the level of creatinine in the blood, improve GFR, increase the content of 25-hydroxyvitamin D and reduce pro-inflammatory cytokines, which has a positive effect on the functional state of the kidneys and allows them to slow down or even prevent the development and progression of diabetic nephropathy in patients with DM.