Biochemical markers of bone turnover in the diagnosis of renal osteodystrophy in dialyzed children

In this study we investigated the value of biochemical markers of bone turnover in the diagnosis of renal osteodystrophy in dialysis patients. The study was carried out in 22 chronic renal failure patients (mean age: 16.1+/-4.5) being treated with chronic dialysis. There were three groups according to intact parathormone (iPTH) levels: Group I (n: 6): iPTH levels were less than 200 pg/ml; Group II (n: 9): iPTH levels were between 201 and 500 pg/ml; and Group III (n: 7). iPTH levels were higher than 501 pg/ml. We investigated iPTH, bone alkaline phosphatase, total serum alkaline phosphatase, osteocalcin, serum type I procollagen peptide (PICP) and insulin-like growth factor-1 (IGF-1) levels in all patients. In group III mean bone alkaline phosphatase level (126.0+/-10.95) was significantly higher than in both group I and group II (52.16+/-22.8, 57.35+/-16.21) (p<0.001). Mean osteocalcin level (35.13+/-2.93) in group I was significantly lower than in group III (40.52+/-2.83) (p<0.05). Serum alkaline phosphatase, PICP and IGF-1 levels were not different between the groups (p>0.05). There was a significant positive correlation between bone alkaline phosphatase and iPTH (r=0.80, p<0.0001). Serum osteocalcin correlated with both bone alkaline phosphatase and iPTH (correlation) coefficients were r=0.44 and r=0.51 respectively, p<.05. It is concluded that bone alkaline phosphatase and osteoocalcin combined with iPTH level seem to be useful noninvasive markers of bone metabolism in dialysis patients.