BIOCHEMICAL MARKERS OF RENAL OSTEODYSTROPHY IN PEDIATRIC-PATIENTS UNDERGOING CAPD CCPD

Serum intact PTH [1-84] levels were evaluated as a potential non-invas ive method for the diagnosis of renal osteodystrophy in children treat ed with CAPD/CCPD. Sixty-eight bone biopsy samples were obtained from 55 patients, aged 13 +/- 5 (X +/- SD) years, undergoing CAPD/CCPD for 29 +/- 13 months; osteitis fibrosa was present in 34 cases, mild lesio ns of secondary hyperparathyroidism in six, 15 had adynamic lesions, a nd 13 were classified as normal histology. Serum calcium levels were h igher in patients with adynamic bone or normal bone histology than in those with secondary hyperparathyroidism, whereas serum phosphorus, al kaline phosphatase and PTH levels were greater in patients with osteit is fibrosa. The combination of a serum PTH level >200 pg/ml and a seru m calcium value < 10 mg/dl was 85% sensitive and 100%, specific for id entifying patients with high-turnover lesions of bone. Serum PTH value s <200 pg/ml were 100% sensitive but only 79% specific for patients wi th adynamic bone; specificity increased to 92%, however, using the com bined criteria of a PTH level <150 pg/ml and a serum calcium level >10 mg/dl. Higher serum calcium levels and serum PTH values within or bel ow the normal range characterize patients with the adynamic lesion of renal osteodystrophy. Serum PTH levels of approximately 200 pg/ml are useful for distinguishing patients with low-turnover lesions of renal osteodystrophy from those with secondary hyperparathyroidism.