Background: Diabetes mellitus is the most common cause of end stage kidney disease in the developed countries. Chronic kidney disease-mineral and bone disorder (CKD-MBD) develops with deteriorating of the renal functions. Diabetic patients on hemodialysis are characterized by low bone turnover, higher prevalence of severe and progressive vascular calcification with increased cardiovascular morbidity and mortality. The main factor which causes vascular calcification in patients with diabetic kidney disease (DKD) is poor glycemic control. The recent trial findings describe an inverse correlation between intact parathyroid hormone (iPTH) serum levels and glycemic control in a group of diabetic patients on hemodialysis.
Aim: The objective of the proposed project is to access the difference of the laboratory markers MBD in the group of patients with 3rd stage DKD depending on glycemic control. We focused on the relationship between the glycemic compensation of diabetes (HbA1c) and iPTH serum level.
Patients and method: Ninety one patients with 3rd stage DKD were investigated. There were 46 women (50.5 %) and 45 men (49.5 %), average age of patients was 71.2 ± 7.0 years, with creatinine level 128 ± 30 μmol/l and estimated glomerular filtration (eGF, MDRD) 0.82 ± 0.16 ml/s. There were 60 patients with better glycemic control of diabetes (HbA1c < 7 %) vs 29 patients with poorly controlled diabetes (HbA1c > 7 %). MBD markers were compared in both groups. Patients were further stratified into subgroups based on the serum level of iPTH (iPTH < 35 pg/ml vs iPTH > 35 pg/ml) and MBD markers compared. Statistical analysis was performed using and Mann-Whitney test.
Results: We have found the statistical significance in the serum phosphate and proteinuria levels in between groups with HbA1c < 7 % vs patients with HbA1c > 7 %. Diabetics with better glycemic control had significant reduction in serum phosphate level (1.14 ± 0.20 vs 1.23 ± 0.18 mmol/l, p = 0.038) and in 24 hrs proteinuria level (0.56 ± 1.35 vs 1.30 ± 1.61 g/day, p = 0.007). In the group of presumed low bone turnover (iPTH < 35 pg/ml) we have found the trend towards increased serum calcium level (2.49 ± 0.12 vs 2.43 ± 0.10 mmol/l, p = 0.063) and increased HbA1c value (7.5 ± 1.8 vs 6.4 ± 1.6 %, p = 0.023).
Conclusion: Our results suggest the closer relationship between glycemic control of diabetes and mineral-bone disorder in earlier stages of DKD.
Key words: diabetes mellitus type 2 (DM2T) - chronic kidney disease (CKD) - mineral and bone disorder (MBD).