Growth Outcomes in Individuals with Idiopathic Short Stature Treated with Growth Hormone Therapy

The few studies that have evaluated the long-term height outcomes following growth hormone (GH) treatment in children with idiopathic short stature (ISS) have shown a growth response to GH treatment similar to that in GH-deficient children. A literature search of all randomized and nonrandomized studies of GH treatment in children with ISS from prepubertal years to adult height or near-adult height published over the last 10 years identified six publications (none was a classic meta-analysis). Several studies showed a dose-dependent response in height outcome. Overall, the younger the patient and the greater the difference in current height vs. parental height at start of treatment, the more substantial the gain in height. Height improvement ranged from 0.5 to 1.3 standard deviation score (SDS). The magnitude of height gain was substantial, even after adjustment for growth changes in control subjects (0.5 to 1 SDS), and it was comparable to that seen in other non-GH-deficient syndromes. Only two studies reported data from matched control subjects. Interestingly, there was no difference in height gain between familial short stature and non-familial short stature after adjusting for spontaneous height gain to adult age in non-GH-treated control subjects. To summarize, patients with ISS can benefit from GH treatment with respect to growth outcome, with results maintained into adulthood.