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.