LONG-TERM RESULTS OF GROWTH-HORMONE THERAPY IN CHILDREN WITH SHORT STATURE, SUBNORMAL GROWTH-RATE AND NORMAL GROWTH-HORMONE RESPONSE TO SECRETAGOGUES

BACKGROUND AND OBJECTIVE Growth hormone treatment in children with idi opathic short stature (ISS) leads to growth acceleration in the first years, but the effect on final height is still poorly documented. We t herefore studied the long-term effect of GH therapy in children with i diopathic short stature. DESIGN We have treated 27 prepubertal childre n with ISS with recombinant human GH (rhGH) in an initial dosage of 2 IU/m(2) body surface/day subcutaneously, which was doubled either afte r the first year if the height velocity increment was less than 2 cm/y ear, or thereafter if height velocity fell below the P50 for bone age. Growth and bone maturation of the treatment group (ISS group, n=21) w ere compared to those of an untreated control group with ISS (ISS cont rols, n=27) and of a group of rhGH treated children with isolated GH d eficiency (GHD group, n=7). RESULTS In 9 patients of the ISS group sti ll on treatment, height standard deviation score (HSDS) for chronologi cal age increased from -3.8+/-0.7 to -2.3+/-0.9 (mean+/- standard devi ation) over 6 years, while in matched ISS controls HSDS for age did no t change. HSDS for age in the GHD group increased from -3.9+/-0.6 to - 1.8+/-0.7 after 4 years, significantly more than the ISS group. Bone m aturation was accelerated in the ISS and GHD groups. HSDS for bone age and predicted adult height did not change in either group. Final heig ht in 12 children of the ISS group was -2.6+/-1.0 SDS. In the untreate d controls final height was similar. A low integrated GH concentration over 24 hours, a low GH peak to provocative stimuli, and minimal init ial BA delay predicted a favourable outcome. CONCLUSION rhGH treatment in this group of children with idiopathic short stature did not incre ase average final height. Part of the heterogeneity of the response ca n be attributed to the variation in endogenous GH secretion and initia l bone age delay.