Final height in children with idiopathic growth hormone deficiency treated with recombinant human growth hormone: the Belgian experience

Background: The growth response to recombinant hGH (rhGH) treatment and final height of 61 Belgian children (32 boys) with idiopathic growth hormone deficiency (GHD) were studied.

Patients/methods: Two patient groups were compared: Group 1 with spontaneous puberty (n = 49), Group 2 with induced puberty (n = 12). The patients were treated with daily subcutaneous injections of rhGH in a dose of 0.5-0.7 IU/kg/week (0.17-0.23 mg/kg/week) from the mean +/- SD age of 11.9 +/- 3.1 years during 5.1 +/- 2.1 years.

Results: rhGH treatment induced a doubling of the height velocity during the first year and resulted in a normalisation of height in 53 (87%) patients. Final height was -0.7 +/- 1.1 SDS, being 170.4 +/- 7.2 cm in boys and 158.0 +/- 6.4 cm in girls. Corrected for mid-parental height, final height was 0.0 +/- 1.1 SDS. Ninety-two percent of the patients attained an adult height within the genetically determined target height range. Although height gain during puberty was smaller in the patients with induced puberty (boys: 17.1 +/- 7.0 cm vs. 27.5 +/- 6.6 cm (p < 0.005); girls: 9.6 +/- 7.4 cm vs. 22.2 +/- 6.1 cm (p < 0.005)), no differences in final height after adjustment for mid-parental height were found between patients with spontaneous or induced puberty.

Conclusions: We conclude that patients with idiopathic GHD treated with rhGH administered as daily subcutaneous injections in a dose of 0.5-0.7 IU/kg/week reach their genetic growth potential, resulting in a normalisation of height in the majority of them, irrespective of spontaneous or induced puberty.