Evaluation of Insulin-Like Growth Factor-1 and Its Impact on Growth Hormone Therapy in Growth Hormone-Deficient Indian Children

Background: Insulin-like growth factor-1 (IGF-1) and IGF-binding protein 3 (IGFBP-3) are used widely for evaluating growth hormone deficiency (GHD). We evaluated the effect of recombinant human growth hormone treatment on serum IGF-1 concentrations in Indian children with GHD over a period of 24 months. Patients and Methods: Patients who presented with short stature were evaluated. The enrolled subjects exhibited a height standard deviation score (SDS)of less than -3 and/or a height velocity SDS of less than - 2 over a 12-month period, and they displayed GH concentrations of less than 10 ng/ml in 2 provocative tests. Patients received a detailed physical examination that included auxology, pubertal staging, and biochemical assays to measure IGF-1 concentration. All patients received GH at a dose of 0.3 mg/kg/week in 7 divided doses subcutaneously daily at night. Patients with multiple pituitary hormone deficiencies received additional substitution therapy. Results: Twenty-five prepubescent children (male: female = 14: 11) at a mean age of 8.6 +/- 2.9 years were enrolled. The height SDS at baseline, 1 year, and 2 years was - 5.38 +/- 1.4, - 4.10 +/- 1.4, and - 3.6 +/- 1.3, respectively (P < 0.005), whereas the IGF- 1 SDS at baseline, 1 year, and 2 years was - 3.40 +/- 0.8, - 1.74 +/- 1.2 and, - 1.54 +/- 1.7, respectively (P > 0.1). No significant difference in height change SDS was detected between children with an IGF-1 SDS in the normal range and children with an IGF- 1 SDS of less than -2 at 2 years. Bone age advancement, the occurrence of puberty, and levels of fasting glucose and HbA1C did not change during therapy. Conclusions: Our study on Indian children indicates that changes in serum IGF- 1 SDS concentrations may not be a reliable marker for responsiveness to GH therapy. (C) 2011 Kowsar M.P.Co. All rights reserved.