Bone Activity Biomarkers and Bone Mineral Density in Children with Chronic Kidney Disease

Abstract

Introduction: Chronic kidney disease - mineral and bone disorder (CKD-MBD) is a spectrum of bone minerals changes that range from high turnover lesions of secondary hyperparathyroidism to the low turnover lesions of adynamic bone disease. Bone biopsy is the gold standard for the diagnosis, but it is not routinely performed because it is invasive technique. Methods: Fifteen CKD children on regular hemodialysis (group I) and 15 CKD children on conservative management (group II) were selected from the nephrology clinics of Zagazig University Hospitals along with 15 age and sex-matched healthy controls. Participants were subjected to biochemical assessment that included osteocalcin (OC), total and bone-specific alkaline phosphatase (tALP and bALP), isomerized beta form of type I collagen cross-linked telopeptide (β-Crosslaps) and intact parathyroid hormone (iPTH) levels. Patients with CKD also had their bone mineral density (BMD) measured using dual energy X-ray absorptiometry (DEXA) at lumbar spine and femoral neck. Results: Serum β-Crosslaps, OC and bALP were significantly higher in patient groups than controls and in group I compared to group II .There was a negative significant correlation between mean Z-score at lumbar spines and bALP, OC and iPTH in group I and with β-Crosslaps in both patient groups. The mean Z-score at femoral neck correlated negatively with bALP in group I, with OC in group II and with iPTH and β-Crosslaps in both groups. Conclusion: Biochemical bone markers and assessment of BMD in patients with CKD may have a role in the early detection of CDK-MBD. Keywords: chronic kidney disease; bone mineral density; bone biomarkers