Endocrine Abstracts

Introduction: Factors that affect the response to growth hormone (GH) treatment in GH-deficient adults are not certain. We performed a retrospective analysis of our data to determine the effect of age and sex hormone replacement on growth hormone replacement dose and IGF-1 levels in growth hormone deficient adults.

Patients and Methods: 146 patients (73F/73M, age range 18-84 years) were referred for growth hormone replacement between 1997 and 2001. The IGF-1 level was estimated at baseline. The patients were started on a standard dose of 0.1mg subcutaneously, once daily and the dose of GH was titrated every six weeks till IGF-1 achieved mid-normal range for age. The dose of GH thus achieved was the maintenance dose. We recorded the IGF-1 levels at baseline and at titration visits, the dose of growth hormone and the type of sex hormone replacement (oral, patch, injection or implant). Responsivity to GH was defined as the ratio of GH induced DELTAIGF-1 to dose used in the same period.

Results: Of the female patients, 37 were on an oral preparation, 14 on transdermal patches and 22 were not taking any type of oestrogen replacement. 14 males were not taking testosterone replacement; 59 were on a parenteral testosterone preparation (37 on Sustanon injection, 16 on testosterone implants and 6 on transdermal patches). In multiple regression analysis, the post-treatment IGF-1 and responsivity were significantly correlated with age (p=0.003), the baseline IGF-1 (p=0.01) and the maximum dose of GH administered (p=0.004), but not with sex (p=0.97), sex hormone replacement or the route of its administration (p=0.67).

Conclusion: In our study, the IGF-1 levels following growth hormone administration was significantly correlated with age; but contrary to some previous studies not with sex or sex hormone replacement. Effect of sex hormone replacement on IGF-1 and dose of growth hormone needs to be studied further.