Plasma osteoprotegerin is an independent risk factor for mortality and an early biomarker of coronary vascular calcification in chronic kidney disease

Background: Cardiovascular disease is the major cause of morbidity and mortality in chronic kidney disease (CKD) and early biomarkers are required which can predict disease and death in such patients. The aim of our study was to investigate if osteoprotegerin (OPG) could be a predictor of coronary artery calcification (CAC) and mortality in CKD. Methods: A total of 77 outpatients (32 with pre-dialysis CKD and 45 undergoing hemodialysis) were followed-up during 2 years. Measurements of CAC were performed using Siemens Multidetector CT software and calcium scores were measured according to the Agatston method. Results: OPG was an independent predictor of the Agatston score for CAC and correlated with the degree of CAC in pre-dialysis patients. A two-sample t-test characterized survivors as having a better glomerular filtration rate, lower Agatston scores, and lower serum levels of OPG. Kaplan-Meier survival curves separated survivors from non-survivors at plasma OPG cut-off levels of < 3.1 ng/mL. A multivariable logistic regression analysis showed that OPG was an independent predictor of mortality from all causes in CKD patients. Conclusions: OPG predicted mortality in CKD patients and could be a valuable biomarker in early detection of CAC in these patients.