Prevalence and risk factors of vascular calcification in pre-dialysis patients with Balkan endemic nephropathy

Introduction Vascular calcifications (VC) are common in patients with chronic kidney disease and present one of manifestations of mineral and bone disorders in these patients. Objective The aim of this pilot study was to examine the prevalence and risk factors of VC in pre-dialysis patients with Balkan endemic nephropathy (BEN) and other kidney diseases. Methods The study involved 32 pre-dialysis patients, 15 with BEN and 17 with other kidney diseases. All the patients underwent an interview, objective examination, routine laboratory analyses and measurement of serum concentration of intact parathyroid hormone (iPTH), 25-hydroxyvitamin D3 [25(OH)D3] and osteopontin. VCs in iliac, femoral, radial, and digital arteries were evaluated and Adragao VC score was calculated. The samples of radial artery were collected during the first creation of an arteriovenous fistula, and expression of osteocalcin, bone morphogenic protein-2 osteopontin, and matrix Gla-protein in arterial wall were examined. Results Patients with BEN were significantly older (71.1 +/- 6.1 vs. 54.7 +/- 11.1 years), but they had significantly lower systolic and mean blood pressure (95.7 +/- 13.2 mmHg vs. 104.3 +/- 7.4 mmHg) and lower serum concentration of phosphorus (1.32 +/- 0.36 mmol/l vs. 1.65 +/- 0.35 mmol/l) and cholesterol (4.3 +/- 1.1 mmol/l vs. 5.2 +/- 0.8 mmol/l) than patients with other kidney diseases. Mean VC score was significantly lower in patients with BEN than in those with other kidney diseases (2.8 +/- 1.7 vs. 4.6 +/- 1.8; p = 0.009), but expression of four examined proteins in arterial wall differed insignificantly between the two groups. VC score correlated significantly with serum concentrations of cholesterol, triglycerides (positively), and iPTH (negatively). Conclusion Pre-dialysis BEN patients had a significantly lower mean score of VC than patients with other kidney diseases.