Growth hormone measurements versus auxology in treatment decisions: the Australian experience.

Growth hormone (GH) therapy is regulated in Australia by an expert national government committee. A national database (OZGROW) enables regular audits and rational guideline revisions. In 1988 the guidelines were revised to allow eligibility on auxologic criteria alone because of difficulties in diagnosing GH deficiency (GHD) and GH responses in non-GH-deficient children. Initial entry criteria were height less than the 3rd percentile and growth velocity less than the 25th percentile of bone age. Growth hormone testing was continued in most children. More than 3100 children have been treated since 1988 (35 percent with GHD, 12.5% with Turner syndrome, and 52% with other non-GHDs). Five-year responses (change in height SD scores) were best in the group with complete GHD (+2) (which received the lowest dose of GH) and similar in other groups, including those with partial GHD (+1.5). The increase in final height is 4 to 6 cm in subjects with Turner syndrome. This data is not yet available for subjects with other non-GHDs. In 1994 the guidelines were revised to restrict use of GH therapy to subjects with height less than the 1st percentile, and cessation of GH therapy was brought forward to bone age 13.5 years for girls and 15 years for boys. Subjects with maturational delay were excluded because of the finding that in the presence of significant bone age delay height prognosis was good. New patient accruals have decreased since 1992, from 100/yr to less than 50/yr. Expenditures have also fallen, from $31 to $16 in 1994-1995, because of reduced patient numbers and GH pricing. Australian use of GH is 68.7% that of the United States and 42.2% that of Sweden and is in the midrange internationally. In conclusion, an auxology-based GH program coupled with a comprehensive national database enables rational and economic use of GH in short children.