Circulating osteoprotegerin and progression of coronary artery calcification in patients with chronic kidney disease: the KoreaN Cohort Study for Outcome in Patients With Chronic Kidney Disease (KNOW-CKD)

Coronary artery calcification (CAC) is a surrogate of cardiovascular events in patients with chronic kidney disease (CKD). To establish the role of circulating osteoprotegerin (OPG) as a cardiovascular biomarker in patients with CKD, we investigated whether an increase in serum OPG levels is associated with the risk of CAC progression. A total of 1,130 patients with CKD stage 1 to predialysis 5 were divided into quartiles according to serum OPG levels (Q1 to Q4). The coronary artery calcium score (CACS) was assessed at baseline and at the 4-year follow-up visit. CAC progression was defined as an increase in the CACS of more than 200 Agatston units over 4 years. Serum OPG levels were positively correlated with the CACS at baseline (R = 0.240, p < 0.001) and at the 4-year follow-up visit (R = 0.280, p < 0.001) as well as with changes in the CACS for 4 years (R = 0.270, p < 0.001) based on scatter plot analysis. Binary logistic regression analysis demonstrated that the risk of CAC progression was significantly increased in Q4 compared with Q1 (adjusted odds ratio, 3.706; 95% confidence interval, 1.154-11.902). Penalized spline curve analysis revealed a linear association between serum OPG levels and the risk of CAC progression. An increase in circulating OPG levels was associated with the risk of CAC progression in patients with predialysis CKD.