Correlation among markers of renal osteodystrophy in pediatric hemodialysis patients.

Serum levels of parathyroid hormone (PTH), alkaline phosphatase (AP), and calcium (Ca2+) have been used to evaluate renal osteodystrophy (RO) in adult patients undergoing dialysis. Osteocalcin (BGP) is a bone protein which also serves as a marker for bone turnover. Serum BGP levels correlate positively with rates of bone turnover and serum concentrations of PTH, AP, and Ca2+ in various studies of adult end-stage renal disease (ESRD) patients, whereas other studies reveal BGP to be a poor indicator of bone turnover in ESRD. RO is a significant problem in pediatric ESRD patients; however, there have been few studies evaluating the correlation of markers for RO in children with ESRD. We measured serum PTH, AP, Ca2+, and BGP levels in a group (n=23) of pediatric patients with ESRD and assessed the correlation among the markers. There was a positive correlation between serum PTH and AP (r=0.658, p<0.001). In contrast, there was no correlation between either serum Ca2+ or BGP, and either PTH or AP. The correlation between Ca2+, BGP and either PTH or AP was unaffected by growth in our patient population. Finally, neither age nor pubertal stage improved the correlation between either Ca2+ or BGP, and either PTH or AP. We conclude that serum PTH and AP are useful markers for RO, whereas calcium and BGP levels should not be used to evaluate RO in pediatric ESRD patients.