Children with chronic kidney disease: a 3-year prospective study of growth, bone mass and bone turnover

Aim: Children with chronic kidney disease (CKD) are at risk of developing skeletal problems. This 3-year prospective study investigated the development of bone mass and bone turnover in children with CKD. Methods: Fifteen patients, 4-15 years, were included with a median glomerular filtration rate of 48 (range 8-94) mL/min/1.73 m(2). Bone mineral density (BMD) and markers of bone and mineral metabolism were investigated over a 3-year period. Results: Growth was satisfactory but a delayed bone age was observed. Total body bone mineral density (TBBMD) Z-scores were below zero in five patients at start and after 3 years, but none had a Z-score below -2.5. Lumbar spine BMD Z-scores were below zero in three patients at start and in five patients after 3 years. The median TBBMD and lumbar spine Z-scores did not change during the study period. Eleven CKD patients had increased PTH levels at baseline and 13 patients after 3 years. Most children had normal levels of leptin and vitamin D. Almost 50% of the patients had increased osteoprotegerin levels after 3 years. Conclusion: A normal BMD does not exclude mineral bone disorder in patients with CKD, yet the BMD Z-scores were well preserved and most markers of bone turnover were within the reference intervals.