Weight relative to height before and during growth hormone therapy in prepubertal children.

We used the Genentech National Cooperative Growth Study database to examine differences in weight relative to height (weight for height standard deviation score or WTHTZ) in 3460 patients at enrollment and after one year of therapy with recombinant human growth hormone (rhGH), and in a subset of 450 patients treated for three years with rhGH. The major diagnostic categories were idiopathic growth hormone deficiency (IGHD), organic GH deficiency (OGHD), and idiopathic short stature (ISS). Children with IGHD and ISS were underweight for height at baseline but had a progressive increase in WTHTZ during three years of rhGH therapy. The same pattern applied to children with IGHD associated with septo-optic dysplasia and CNS trauma or infection. However, children with OGHD associated with craniopharyngiomas, other CNS tumors, leukemia, or CNS irradiation were overweight when starting rhGH and showed a decrease in WTHTZ during the first year of rhGH therapy. The increase in WTHTZ during rhGH treatment in children with ISS and OGHD suggests that the GH-induced increase in muscle mass exceeded loss of fat mass. Because children with neoplasm-related OGHD were overweight at baseline, the decline in WTHTZ during the first year of rhGH therapy suggests that loss of fat mass is the predominant effect in this subgroup.