Relevance of IGF-I, IGFBP-3, and IGFBP-2 measurements during GH treatment of GH-deficient and non-GH-deficient children and adolescents

Background. Little information is available on the relevance of parameters representing the insulin-like growth factor (IGF) system with regard to gro wth hormone (GH) treatment during childhood. In adults, high IGF-I levels w ere found to be associated with side effects and longterm risks. Aim/Method . Our aim was to monitor the serum levels of IGF-I, IGF-binding protein (IG FBP) 3, and IGFBP-2 during long-term GH treatment of 156 patients with GH d eficiency (GHD) and of 153 non-GHD patients. We determined the extent to wh ich the IGF parameters exceed the normal ranges and identified those parame ters which are predictive of 1st-year growth. Results: In prepubertal GHD c hildren, the levels of IGF-I, IGFBP-3, and IGF-I/IGFBP-3 exceeded the 95th centile of the reference values for this age group in 2.3, 0.3, and 7.9% of the cases, respectively, whereas in prepubertal non-GHD children, the same parameters exceeded the 95th reference centile in 20.1, 3.5, and 32.2%, re spectively. In pubertal GHD children IGF-I, IGFBP-3, and IGF-I/IGFBP-3 leve ls exceeded the 95th reference centile in 11.1, 1.5, and 15.4%, respectivel y. In pubertal non-GHD children, these levels also exceeded the 95th centil e in 26.7, 7.0, and 41.4%, respectively. In both GHD and non-GHD groups, ho wever, some patients had IGF parameters which were below the reference valu es. Our analysis showed that, in both groups, in addition to maximum GH, al l IGF parameters(IGF-I, IGFBP-3, IGF-I/IGFBP-3 ratio, IGFBP-2 or derivative s) significantly extend the scope of a calculated model for predicting 1st- year height velocity. Conclusion: For reasons of safety and optimization of GH therapy, it is essential to follow up IGF-I, IGFBP-3, and IGFBP-2 level s regularly during childhood. Copyright (C) 2001 S. Karger AG, Basel