Idiopathic Short Stature: Conundrums of Definition and Treatment

Children with idiopathic short stature (ISS) are statistically defined by height SDS < -2 for their bone age and should be distinguished from children with familial short stature for whom height SDS corresponds to mean parental SDS and from the most common explanation for short stature referred to pediatric endocrinologists, constitutional delay in growth and maturation (CDGM), in which there is normal height for bone age and predicted normal adult stature. Low IGF-I levels reported in ISS may be the result of subtle undernutrition or reference to standards appropriate for chronologic age but not osseous maturation in CDGM inappropriately labeled as ISS. While growth hormone (GH) treatment of ISS may add 4-5 cm to adult height, meta-analysis indicates that there is no documented evidence that such treatment improves health related quality of life or psychological adaptation. Thus, the estimated cost of US$52 000/inch gained is difficult to justify. Absence of data regarding efficacy of the use of IGF-I for treatment of ISS has been noted in a recent consensus statement from the North American and European pediatric endocrinology societies. This report further emphasizes the importance of discouraging the expectation that taller stature from GH treatment will improve quality of life.