Introduction

The purpose of monitoring adults who receive growth hormone (GH) replacement therapy is to allow the gathering of information that will enable the clinician to estimate the benefits and possible side effects of treatment, note whether these are transient or long-term and, if side effects occur, determine how these are best managed. Monitoring allows the clinician to determine the appropriate dose of GH replacement, whether this new and relatively expensive therapy is beneficial to an individual patient and enables a decision regarding the duration of treatment, potentially lifelong, to be made. Before we can be in a position to detect unusual or abnormal situations we must be aware of the normal responses in the adult receiving GH replacement therapy.

Although the number of adults receiving GH replacement therapy is increasing, treatment with GH has been used most extensively in children with GH deficiency (GHD). The efficacy of GH replacement was monitored by measuring the growth response of the child. Usually GH therapy was continued until the epiphyses had fused and growth ceased. Change in growth velocity is a variable that is easy to measure, occurs as a direct response to GH replacement and is inexpensive in terms of financial cost even if based on measurements at three-monthly intervals. Now that adults with GHD, of either childhood or adult onset, are likely to receive GH therapy for many years of their adult life, what parameters should we measure? Should we use a biological end point such as a change in body composition? Not every centre has access to the optimum facilities required to measure this.