Osteocalcin and carotid-femoral pulse wave velocity in patients on peritoneal dialysis

Vascular calcification is a cardiovascular risk factor in dialysis patients. Vascular calcification involves a complex process of biomineralization resembling osteogenesis, which leads to arterial stiffness. Osteocalcin is the most abundant noncollagenous protein in the bone matrix. It is synthesized in the bone by osteoblasts and reflects the rate of bone formation. The aim of this study was to evaluate the relationship between serum osteocalcin levels and the carotid-femoral pulse wave velocity (cfPWV) in peritoneal dialysis (PD) patients.

Serum intact osteocalcin and cfPWV were measured in 62 PD patients. Those with CfPWV values >10 m/s were defined as the high central arterial stiffness group, while those with values ≤10 m/s were regarded as the low central arterial stiffness group, according to the European Society of Hypertension and of the European Society of Cardiology guidelines.

Seventeen of the 62 PD patients (27.4%) were in the high central arterial stiffness group. The high central arterial stiffness group were older (P = 0.002), had a longer PD vintage (P = 0.018), and had higher serum osteocalcin levels (P = 0.001) than those in the low group. Multivariate logistic regression analysis showed that the osteocalcin level (odds ratio: 1.069, 95% confidence interval (CI): 1.005-1.137, P = 0.035), PD vintage (odds ratio: 1.028, 95% CI: 1.010-1.048, P = 0.003), and age (odds ratio: 1.081, 95% CI: 1.005-1.162, P = 0.035) were independently associated with central arterial stiffness in PD patients. Among these patients, cfPWV (β: 0.216, P = 0.001) values and log-transformed intact parathyroid hormone (β: -'0.447, P < 0.001) levels were independently associated with the osteocalcin level in PD patients after multivariate forward stepwise linear regression analysis.

Older PD patients with a longer PD vintage and higher serum osteocalcin levels had higher central arterial stiffness as measured by cfPWV. The serum osteocalcin level is an independent marker of central arterial stiffness in PD patients.