Biochemical markers of renal osteodystrophy in pediatric patients undergoing CAPD/CCPD

Abstract

Serum intact PTH [1-84] levels were evaluated as a potential non-invasive method for the diagnosis of renal osteodystrophy in children treated 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 lesions of secondary hyperparathyroidism in six, 15 had adynamic lesions, and 13 were classified as normal histology. Serum calcium levels were higher in patients with adynamic bone or normal bone histology than in those with secondary hyperparathyroidism, whereas serum phosphorus, alkaline phosphatase and PTH levels were greater in patients with osteitis fibrosa. The combination of a serum PTH level > 200 pg/ml and a serum calcium value < 10 mg/dl was 85% sensitive and 100% specific for identifying patients with high-turnover lesions of bone. Serum PTH values < 200 pg/ml were 100% sensitive but only 79% specific for patients with adynamic bone; specificity increased to 92%, however, using the combined 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 below 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.

Diagnostic Accuracy of Bone Turnover Markers and Bone Histology in Patients With CKD Treated by Dialysis

“…Unfortunately, the addition of bALP or other biomarkers did not prove to be clinically useful beyond the diagnostic value of PTH in the assessment of bone turnover. Consistent with other studies, serum PTH levels correlated with bone turnover 14,23,[31][32][33] ; however, to date, PTH levels have not been found to be a strong discriminator among low, normal, and high bone turnover. The present analysis demonstrates that iPTH can be used to discriminate low turnover from nonlow turnover with iPTH values consistent with those recommended by both NKF-KDOQI and KDIGO (Table 4).…”

A structural approach to the assessment of fracture risk in children and adolescents with chronic kidney disease

“…Whereas early case series of bone biopsy results in children on maintenance dialysis reported high-turnover bone disease (osteitis fibrosa and mild lesions of secondary hyperparathyroidism) in the vast majority of patients [8][9][10], more recent series identified adynamic bone in a substantial proportion (27-33%) of children and adolescents [11][12][13]. The implications of low bone turnover for bone structure and strength during growth are not known; however, this bone lesion is associated with increased fracture risk in adults [14] -perhaps due to impaired microfracture repair.…”

Value of the New Bone Classification System in Pediatric Renal Osteodystrophy

“…All of the subjects were part of various clinical investigations to characterize the spectrum of renal osteodys-trophy in pediatric dialysis patients (3,(7)(8)(9)(10)(11); only baseline biopsies were used for the current analysis. All patients received calcium-based phosphate binders at the time of the bone biopsy, and in those treated with daily oral calcitriol, such therapy was held for 4 weeks before bone biopsy.…”

“…Traditionally, renal osteodystrophy has been diagnosed by bone histomorphometry and classified according to lesions of bone turnover ranging from high rates of bone formation (mild lesions of secondary hyperparathyroidism and osteitis fibrosa) to low turnover (adynamic bone) (1,2). However, alterations in skeletal mineralization and bone volume also occur in a substantial proportion of pediatric patients with CKD (2,3) and may contribute to the increased fracture rates, boney deformities, poor linear growth, and chronic bone pain that persist despite adequate control of secondary hyperparathyroidism (4).…”