Combined Evaluation of IGF-1 and IGFBP-3 as an Index of Efficacy and Safety in Growth Hormone Treated Patients

Objective: Measurement of serum insulin-like growth factor-1 (IGF-1) and IGF binding protein-3 (IGFBP-3) levels has been recommended as a useful index for monitoring of growth hormone (GH) therapy in GH deficient children. In this study we aimed to evaluate IGF-1/IGFBP-3 molar ratio during GH treatment as an index of safety and efficacy.
Methods: Serum IGF-1 and IGFBP-3 levels and molar ratio of IGF-1/IGFBP-3 were evaluated in 50 GH deficienct children, during 3 years of GH therapy and these parameters were compared with the growth response.
Results: All patients completed the first year, 38 the second year and 26 the third year of therapy. Although 15 patients in the first year, 5 patients in the second year, and 5 patients in the third year had high IGF-1 SDS values, height increments were similar in the low IGF-1 group and in the normal or high IGF-1 level groups. Molar ratios were also not statistically different between the groups. Molar ratio of IGF-1/IGFBP-3 seemed to be more reliable in evaluating the efficacy than basal IGF-1 level.
Conclusions: Evaluation of the molar ratio of IGF-1/IGFBP-3 may be recommended as a tool to monitor GH treatment and it may be possible to individualize GH treatment accordingly.