baseline igfbp - 3 as the key element to predict growth response to growth hormone and igf - 1 therapy in subjects with non - gh deficient short stature and igf - 1 deficiency

Background: short stature in children represents a heterogeneous group with different etiologies. primary insulin like growth factor 1 (igf 1) deficiency in short stature can present with normal or elevated growth hormone (gh) production. currently there is no model that can reliably predict response to recombinant (r)gh therapy and/or rigf 1 therapy in children with non gh deficient short stature. hypothesis: baseline insulin like growth factor binding protein 3 (igfbp 3) along with ∆ igf 1 in the first 3 months of gh therapy level can be a marker of growth response to the rgh and/or rigf 1 therapy in children with non growth hormone deficiency short stature. objectives: to study the relationship between baseline igfbp 3 and igf 1 levels and the response to rgh and rigf 1 therapy in children with short stature, normal gh secretion and low igf 1 sds. methods: 43 children, age 9.07 ± 2.75 years with height -2.72 ± 0.7 sd and baseline igf 1 of -2.76 ± 0.58 sd, who passed the growth hormone releasing hormone (ghrh) stimulation test were included in a retrospective chart review. they were treated with rgh therapy with a mean dose of 0.46 ± 0.1 mg/kg/week. growth velocity (gv), igf 1 and igfbp 3 levels were done at 3 and 6 months of therapy. subjects with poor response to rgh after 6 months of therapy were switched to rigf 1 therapy at 0.24 mg/kg/day for the next 6 months. subjects were divided according to their growth rate into responders to rgh (n = 23); non responders to rgh, responders to rigf 1 (n = 14) and non responders to rgh and rigf-1 (n = 6). results: there was no correlation between gv and peak gh level at ghrh test. growth velocity positively correlated with ∆igf 1 sd among subjects treated with rgh therapy. height sd positively correlated with igfbp 3 sd. baseline igfbp 3 also inversely correlated with gh peak during ghrh test. conclusions: in subjects with short stature and low igf 1 level, baseline igfbp 3 levels can predict the growth response to rgh and/or rigf 1 therapy.