Growth hormone for short children – whom should we be treating and why?

The objective of this paper was to determine systematically the impact of growth hormone (GH)therapy on adult height of children with (so-called) 'idiopathic short stature' (ISS) using the Cochrane Central Register of Controlled Trials, Medline, and the bibliographic references from retrieved articles of randomised controlled trials (RCTs) and non-RCTs from 1985 to April 2010. Inclusion criteria were initial short stature (defined as height >2 standard deviation[SD] below the mean), peak growth hormone responses>10 micrograms per litre (μg/L), prepuberty, no previous growth hormone therapy, and no comorbid conditions that would impair growth. Data extracted were adult height and overall gain in height from baseline measurement in childhood.Three RCTs (115 children) met the inclusion criteria.The adult height of the GH treated children exceeded that of the controls by 0.65 SD score (~4 cm). The mean height gain in treated children was 1.2 SD score compared with 0.34 SD score in untreated children. A difference of ~1.2 cm in adult height was observed between two GH dose regimens. In the seven non-RCTs, adult height of the GH-treated group exceeded that of controls by 0.45 SD score (~3 cm).The authors conclude that 1) GH therapy in children with ISS seems effective in partially reducing the deficit in height as adults, although less so than in other conditions for which GH is licensed; treated individuals remain relatively short compared with normal height peers. 2)Individual responses to therapy are highly variable; further studies are needed to identify responders. 3) High quality evidence from long-term RCTs of GH therapy that continue until adult height is necessary to determine the ideal dosage and long-term safety.