Individualizing growth hormone dosing in children

Much has been learned over the last three decades regarding the management of growth hormone (GH) treatment in children and adolescents. Current GH therapy enables most GH-treated children to attain a final height within the normal range and close to their target height. However, an optimal outcome is not always achieved and the approach to GH dosing differs among physicians and between countries. Furthermore, the individual response to GH varies dramatically between children, depending on age, the primary disease for which GH is prescribed and its severity, and other factors. Thus, the necessity to individualize treatment according to the specific needs of each child is being recognized. Consensus does not currently exist as to how to formulate individualized treatment plans. Nonetheless, a clear role for biochemical as well as auxological monitoring approaches has been established. Accurate determination of height velocity and interval height increase (expressed as the change in height z-score) continue to be the most important parameters in monitoring response to treatment. The importance of routinely monitoring serum insulin-like growth factor (IGF)-I and IGF binding protein-3 is an emerging paradigm. Roles have been firmly 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 response to GH therapy through dose adjustment. In the years to come, we expect multiple optimization strategies including approaches such as prediction modeling as well as serum IGF monitoring and dose adjustment to evolve and improve. Currently, trials evaluating the utility of GH dose titration aiming to maintain the IGF-I level within a narrow range are being evaluated. The results of such large prospective randomized trials will surely help identify the value of individualizing GH dosing.