Growth hormone treatment of idiopathic short stature: history and demographic data from the NCGS.

Idiopathic short stature (ISS) is a term used to describe children without an identifiable cause for growth failure; these children comprise the largest group of candidates for growth hormone (GH) therapy. Over the past four decades, clinical trials have examined the efficacy and safety of GH treatment in the ISS population; for many of these trials, interpretation of results has been limited by variability in the criteria for ISS, small numbers of subjects, and a short term of study. Recent trials involving larger GH doses for longer periods suggest greater height improvements, but extrapolation to the larger ISS population is still debated. The National Cooperative Growth Study (NCGS) provides an opportunity to evaluate the treatment trends over time. In 1994, there were 20,279 patients enrolled in the NCGS, and 25% were identified as ISS. The most recent analysis was in 2003, and at that time 47,226 patients were enrolled; but only 17% were identified as ISS. This most recent analysis of patients enrolled in the NCGS provides a framework for examining the impact of this new indication for GH on clinical practice patterns.