Endocrine Abstracts

Background: Vitamin D deficiency has been shown to be a risk factor related to diabetes mellitus (DM). Some studies suggest an association between diabetic kidney disease (DKD) and vitamin D (VD).

Aim: To evaluate the effect of the vitamin D therapy on albuminuria in type 2 DM patients.

Methods: There was a 4-month study (January – April 2017) of 48 participants on stable antihyperglycemic (metformin and/or sulfonylurea) and antihypertensive treatment (including angiotensin II receptor blocker). Patients were randomized into two groups: 24 patients of the I^st group received 2000 IU/day of cholecalciferol for 16 weeks, the II^nd group of 24 patients continued antihyperglycemic and antihypertensive treatment. BMI, glomerular filtration rates (GFR), hemoglobin A1c (HbA1c) were estimated. Inclusion criteria: type2 DM patients with HbA1c ≥7%; GFR >90 ml/min/1.73 m², duration of DM no more than 10 years, controlled arterial hypertension. Exclusion criteria were bone metabolism and liver diseases. Serum 25(OH)vitaminD, low-density lipoprotein cholesterol (LDL-C), HOMA-index, urinary albumin excretion rate (UAER) obtained before and after 4-month period of treatment. Quantitative data are expressed as the mean±S.D. The Student’s t-test was used to compare data before and after VD supplementation. The correlation between variables was assessed using the Pearson correlation coefficient. All information was processed with SPSS 21.0.

Results: The mean age of the participants was (54±6.8) years, BMI – (30.9±2.41) kg/m², HOMA – (6.3±2.30), HbA1c – (7.8±0.85)%, the baseline UAER – (69.8±37.62) mg/24 h, the mean 25(OH)vitamin D – (28.5±5.80) ng/ml, LDL-C – (3.1±0.74) mmol/l. 25 (OH) vitamin D levels were inversely associated with BMI (r=−0.4; P=0.05), HOMA (r=−0.7; P=0.005), UAER (r=−0.7; P=0.005), LDL-C (r=−0.4; P=0.02). Compared with the II^nd group, vitamin D therapy had no significant effect on HOMA, plasma LDL-C concentration and UAER (P>0.5). UAER was reduced but only four patients of 24 had their DKD stage improved.

Conclusion: Strong inverse correlation between 25(OH)vitamin D levels and albuminuria can indicate on benefits of vitamin D supplementation for prevention of DKD in diabetic patients. Although cholecalciferol therapy did not decrease urinary albumin excretion rate and LDL-C concentration significantly in patients with diabetic nephropathy the sample size of our study needs to be enlarged to reinforce data.