Changes in body composition of children with chronic renal failure on growth hormone

Body composition is altered in children with chronic renal failure (CRF) an d contributes to the significant growth failure seen in these children. Rec ombinant human growth hormone (rhGH) has been used in the past several year s to improve the somatic growth of children with CRE To determine if the gr owth achieved in these children occurs concomitantly with body compositiona l changes, seven prepubertal (n=6) and pubertal (n=1) children with chronic renal insufficiency (n=4) and end-stage renal disease (n=3) underwent meas urements of total body fat (FM), fat free mass (FFM), bone mineral density (BMD), total bone mineral mass (TBBM), total body water (TBW), and total bo dy potassium (TBK) before and 6 months after initiation of subcutaneous rec ombinant human growth hormone (rhGH) at 0.35 mg/kg per week. The techniques used included dual-energy X-ray absorptiometry (for measurement of FM, BMD , and TBBM), total body potassium counting (for measurement of TBK), and de uterated water for assessment of TBW. Significant increases in both height and weight were seen following 6 months of rhGH therapy. These increases we re accompanied by significant reductions in FM (4.4+/-1.4 kg vs. 3.6+/-1.2 kg, P=0.002) and percentage fat (18.6+/-3.9% vs. 14.5+/-3.4%, P=0.04), whil e FFM (17.9+/-3.0 kg vs. 20.7+/-3.6 kg, P=0.04) increased significantly as did TBBM (776+/-171 g vs. 844+/-177 g, P=0.001). Increases in TBK, a measur e of body cell mass, were also seen. No difference in total BMD was observe d. Thus, growth in CRF is occurring with repletion of the FFM and TBBM comp artments. Despite these improvements, no change was observed in the body ma ss index (BMI). Measurement of BMI alone does not define the compartmental catabolic losses in FFM.