Role of insulin-like growth factor monitoring in optimizing growth hormone therapy

Much has been learned over the past two decades regarding the management of growth hormone (GH) deficiency in children and adolescents. Current GH therapy under ideal circumstances enables children to attain a final height within the normal range and close to their target height. However, such a successful outcome is not always achieved and the necessity to individualize treatment according to the specific needs of each GH-deficient child is now well recognized. Consensus does not currently exist as to how to formulate individualized treatment plans. Nonetheless, a clear role for a biochemical, as well as an auxological, monitoring approach has been established. Accurate determinations of height velocity and interval height increase (expressed as the change in height Z-score) continue to be the most important parameters in monitoring the response to treatment. The importance of routinely monitoring serum levels of insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 is an emerging paradigm. Firm roles have been established for this approach in the assurance of compliance and safety (particularly to avoid long-term theoretical risks). IGF monitoring also has important potential utility as a tool to assess and optimize the response to GH therapy through dose adjustments. In years to come, we expect the development of multiple GH treatment optimization strategies, including approaches such as prediction modeling, as well as serum IGF monitoring and dose adjustments, to evolve and improve.