Serum Osteoprotegerin Is an Independent Marker of Metabolic Complications in Non-DialysisDependent Chronic Kidney Disease Patients

Abstract

Background: Osteoprotegerin (OPG) belongs to the tumour necrosis factor superfamily and is known to accelerate endothelial dysfunction and vascular calcification. OPG concentrations are elevated in patients with chronic kidney disease. The aim of this study was to investigate the association between OPG levels and frequent complications of chronic kidney disease (CKD) such as anaemia, protein energy wasting (PEW), inflammation, overhydration, hyperglycaemia and hypertension. Methods: One hundred non-dialysis-dependent men with CKD stage 3–5 were included in the study. Bioimpedance spectroscopy (BIS) was used to measure overhydration, fat amount and lean body mass. We also measured the serum concentrations of haemoglobin, albumin, total cholesterol, C-reactive protein (CRP), fibrinogen and glycated haemoglobin (HgbA1c), as well as blood pressure. Results: We observed a significant, positive correlation between OPG and age, serum creatinine, CRP, fibrinogen, HgbA1c concentrations, systolic blood pressure and overhydration. Negative correlations were observed between OPG and glomerular filtration rate (eGFR), serum albumin concentrations and serum haemoglobin level. Logistic regression models revealed that OPG is an independent marker of metabolic complications such as anaemia, PEW, inflammation and poor renal prognosis (including overhydration, uncontrolled diabetes and hypertension) in the studied population. Conclusion: Our results suggest that OPG can be an independent marker of PEW, inflammation and vascular metabolic disturbances in patients with chronic kidney disease.

Association of Circulating Osteoprotegerin Level with Blood Pressure Variability in Patients with Chronic Kidney Disease

“…Elevation of serum OPG level in the subjects with reduced eGFR has been previously reported [ 30 ]. Despite the debate on the role of circulating OPG in atherosclerotic disease [ 31 ], as an experimental study reported that exogenous OPG treatment lead to endothelial and vascular smooth cell dysfunction by promoting the production of reactive oxygen species, which may underlie vascular injurious effects in conditions such as hypertension [ 32 ], the phenotype of OPG-knockout mice ultimately indicates circulating OPG as a biomarker, rather than a mediator, of atherosclerosis, as OPG-deficient mice develop early onset arterial calcification [ 33 ].…”

Serum Osteoprotegerin Is an Independent Marker of Left Ventricular Hypertrophy, Systolic and Diastolic Dysfunction of the Left Ventricle and the Presence of Pericardial Fluid in Chronic Kidney Disease Patients

“…As it was shown in the study of Rymarz et al, OPG was an independent marker which may identify patients with poor prognostic factors, e.g., overhydration in CKD [ 39 ]. Pericarditis is one of the complications of uremia.…”

Left Ventricular Diastolic Dysfunction in Chronic Kidney Disease Patients Not Treated with Dialysis

“…OPG levels rise with kidney function decrease and the cause of its accumulation in uremic state remains unknown [ 44 ]. Rymarz showed that OPG is related with protein energy wasting (PEW), inflammation and metabolic disturbances in CKD patients [ 10 ]. Moreover, in the group of patients with CKD not treated with dialysis elevated OPG concentrations were associated with left ventricular hypertrophy, LVDD and the presence of pericardial fluid [ 9 ].…”

“…eGFR was calculated according to the short Modification of Diet in Renal Disease (MDRD) formula [ 10 ]. GFR in mL/min per 1.73 m 2 = 175 × SerumCr − 1.154 × age − 0.203 × 1.212 (if patient is black) × 0.742 (if female).…”