Growth hormone therapy for 3 years: The OZGROW experience

Objective : To examine the growth response over 3 years of growth hormone deficient (GHD) and non-GHD children who have received growth hormone (GH) in Australia.
Methodology : A retrospective study of a group of patients (1362 children) who commenced GH prior to 1 September 1990. Data were collected at 12 growth centres located in major cities throughout Australia. The data were transferred after informed consent to the national OZGROW database located at the Royal Alexandra Hospital for Children, Sydney, NSW. Of the 1362 children, 898 had received 3 years or more GH therapy and were eligible for this analysis. This cohort was then categorized by diagnosis. Growth response was assessed using height standard deviation score, estimated mature height, growth velocity (GV), GH dose and bone age (years).
Results : For children who completed 3 years therapy, the baseline characteristics among diagnostic groups were similar with mean height standard deviation score (SDS) less than – 3 SDS (except for the malignancy group) and mean GV ranging from 3.5 to 4.4 cm/year. The GV during the first year improved in all groups (7.7-9.4 cm/year) followed by an attenuated response during the second and third years of therapy. After 3 years GH therapy the GHD group with peak levels <10 mU/L demonstrated the greatest change in estimated mature height and height SDS. The GHD group with peak levels between £10 but <20 mU/L had a growth response similar to the non-GHD children for all outcome parameters. Change in bone age ranged from 3.1 to 3.8 years with no differences being noted between the diagnostic groups, nor consistently with pubertal status.
Conclusions : Australian GH guidelines have targeted very short children when compared to other series. This large cohort of non-GHD children has demonstrated short-term benefits of GH therapy; however, the long-term benefit remains unclear until these children reach final adult height.