Effect of growth hormone treatment on adult height of children with idiopathic short stature

Background Short-term administration of growth hormone to children with idi opathic short: stature results in increases in growth rate and standard-dev iation scores for height, However, the effect of longterm growth hormone th erapy on adult height in these children is unknown. Methods We studied 121 children with idiopathic short stature, all of whom had an initial height below the third percentile, low growth rates, and max imal stimulated serum concentrations of growth hormone of at least 10 mu g per liter. The children were treated with growth hormone (0.3 mg per kilogr am of body weight per week) for 2 to 10 years. Eighty of these children hav e reached adult height, with a bone age of at least 16 years in the boys an d at least 14 years In the flirts, and pubertal stage 4 or 5. The differenc e between the predicted adult height before treatment and achieved adult he ight was compared with the corresponding difference in three untreated norm al or short-statured control groups. Results In the 80 children who have reached adult height, growth hormone tr eatment increased the mean standard-deviation scare for height (number of s tandard deviations from the mean height for chronologic age) from -2.7 to - 1.4, The mean (+/-SD) difference between predicted adult height before trea tment and achieved adult height was +5.0+/-5.1 cm for boys and +5.9+/-5.2 c m for girls. The difference between predicted and achieved adult height amo ng treated boys was 9.2 cm greater than the corresponding difference among untreated boys with initial standard-deviation scores of less than -2, and the difference among treated girls was 5.7 cm greater than the difference a mong untreated girls, Conclusions Long-term administration of growth hormone to children with idi opathic short stature can increase adult height to a level above the predic ted adult height and above the adult height of untreated historical control children. (N Engl J Med 1999;340:502-7.) (C)1999, Massachusetts Medical So ciety.