Bone density in renal transplant recipients and in patients with chronic kidney disease: a follow-up study in children and adolescents

Aims: Disturbances in mineral and bone metabolism are common in patients with chronic kidney disease. The purpose of this follow-up study was to compare the change of bone mineral density in patients with chronic kidney disease to those who have received the renal transplant. Methods: The study included 47 children and adolescents: 16 with mild to moderate kidney disease, 14 on dialysis and 17 patients with renal transplant. At the baseline and follow-up visits, regular biochemistry, anthropometry and bone mineral density were measured. To minimize the effect of skeletal size, bone mineral apparent density (BMAD; g/cm(3)) was calculated. Results: The mean height was below one standard deviation from reference values in patients on dialysis and in those with renal transplant. After correction for age, baseline and follow-up BMAD did not differ significantly between patients after transplantation and those with chronic kidney disease. The increase of BMAD between two measurements (mean period 16.0 +/- 4.4 months) was not significantly higher in patients with kidney transplant compared to those with chronic kidney disease. The significant predictors of BMAD were PTH in patients with chronic kidney disease and duration of steroid therapy in patients with renal transplant. Conclusions: The results showed that bone density in children and adolescents, even several years after kidney transplantation, did not significantly change over time comparing to patients with chronic kidney disease. Hyperparathyroidism and steroid therapy were the most important risk factors for the slow increase of bone density.