Short-Term Tools to Measure Responsiveness to Growth Hormone Replacement

Abstract

Growth hormone (GH) replacement is a prolonged and expensive treatment modality which involves daily subcutaneous injections in children and adults. Efforts have been made, therefore, to develop short-term tests to predict long-term clinical response. The so-called insulin-like growth factor I (IGF-I) generation test was originally introduced in order to select responders to GH among short children without classical GH deficiency. A positive correlation between short-term increase in serum IGF-I and linear growth has, however, only been reported in a minority of studies. There is no single outcome measure available in GH-deficient adults, and no evidence of a correlation between IGF-I and the effects of GH replacement on factors such as body composition or physical fitness. In conclusion, no reliable short-term test to predict long-term response to GH replacement is available in either children or adults. For safety reasons, however, measurement of serum IGF-I concentrations in GH-deficient patients remains an important means of monitoring during GH replacement.

Free insulin-like growth factors – measurements and relationships to growth hormone secretion and glucose homeostasis

“…Therefore, as in children, measurements of total IGF-I and IGFBP-3 are also used routinely in adults suspected of GHD. For more extensive reviews on GH secretion and GHD please refer to [37,46,[90][91][92][93][94].…”

What should be the diagnosis and management of short children with normal growth hormone secretion and non-primary IGF-I deficiency?

“…The lack of IGF-I increase during short-term rhGH administration confirms primary IGF-I deficiency and is an approved indication to the therapy with rhIGF-I. Unfortunately, the significance of IGF-I increase during generation test as a predictor of growth response to rhGH therapy has been questioned for many years [18,19]. On the other hand, it has been reported in more recent studies that IGF-I generation test may be predictive on growth response to rhGH therapy in children with GHD or ISS [14,20,21].…”

Dynamic response of C‐type natriuretic peptide and its aminoterminal propeptide (NTproCNP) to growth hormone treatment in children with short stature

“…The addition of pretreatment biochemical parameters, such as serum insulin‐like growth factor‐I (IGF‐I) and peak serum GH level after stimulation, improved the models, as did the addition of rhGH dose. A variety of other biomarkers of growth response have shown promise but none has been shown to correlate with height velocity in normal statured children. Moreover, none is specific to events in the endochondral growth plate, and hence linear growth.…”