Correlation of serum osteocalcin with bone metabolism and mineral markers in maintenance hemodialysis patients

Objective To investigate the level of osteocalcin (bone glaprotein, BGP) in maintenance hemodialysis patients (MHD) and its correlation with bone metabolism and mineral metabolism indexes.Methods We enrolled 36 adult MHD patients from February 2014 to May 2014 in Blood Purification Center, General Hospital of Jinan Military Command. Fasting blood routine laboratory examination was carried out before dialysis extraction. Serum calcium, phosphorus, alkaline phosphatase, intact parathyroid hormone (iPTH, chemiluminescence), fibroblast growth factor 23 (FGF23, ELISA), and osteocalcin (BGP, ELISA) were detected. Pearson correlation and Logistic regression were used to analyze related data.Results The BGP level in 36 patients was (193.59±87.38) g/L, positively correlated with serum phosphorus (r=0.529), FGF23 (r=0.492), and iPTH (r=0.601), negatively correlated with age (r=-0.346), but not with serum calcium (r=0.003), total alkaline phosphatase (r=0.170), and dialysis vintage (r=0.097). According to the level of iPTH, patients were divided into low iPTH group, iPTH control group and high iPTH group, and the statistical analysis showed significant difference in BGP (F=21.365, P=0.0001), FGF23 (F=5.824, P=0.007), serum phosphorus (F=7.739, P=0.002) among the groups, but no significant difference existed in the serum calcium, alkaline phosphatase, and the dialysis vintage among the groups. According to the level of BGP, patients were divided into higher than average level group and below average level group, and Logistics regression analysis revealed that high iPTH (OR=3.49, P=0.042), high FGF23 (OR=3.221, P=0.043) and high phosphorus (OR=3.103, P=0.038) were independent risk factors of BGP higher than average level.Conclusions BGP was significantly elevated in MHD patients, and positively correlated with iPTH, serum phosphorus and FGF23.