To assess the long-term effect of prepubertal high-dose GH treatment on growth in children with idiopathic short stature (ISS).
Design and methods
Forty children with no signs of puberty, age at start 4–8 years (girls) or 4–10 years (boys), height SDS <−2.0 SDS, and birth length >−2.0 SDS, were randomly allocated to receive GH at a dose of 2 mg/m2 per day (equivalent to 75 μg/kg per day at start and 64 μg/kg per day at stop) until the onset of puberty for at least 2 years (preceded by two 3-month periods of treatment with low or intermediate doses of GH separated by two washout periods of 3 months) or no treatment. In 28 cases, adult height (AH) was assessed at a mean (s.d.) age of 20.4 (2.3) years.
GH-treated children (mean treatment period on high-dose GH 2.3 years (range 1.2–5.0 years)) showed an increased mean height SDS at discontinuation of the treatment compared with the controls (−1.3 (0.8) SDS versus −2.6 (0.8) SDS respectively). However, bone maturation was significantly accelerated in the GH-treated group compared with the controls (1.6 (0.4) versus 1.0 (0.2) years per year, respectively), and pubertal onset tended to advance. After an untreated interval of 3–12 years, AH was −2.1 (0.7) and −1.9 (0.6) in the GH-treated and control groups respectively. Age was a positive predictor of adult height gain.
High-dose GH treatment restricted to the prepubertal period in young ISS children augments height gain during treatment, but accelerates bone maturation, resulting in a similar adult height compared with the untreated controls.