PHARMACOLOGICAL TESTING FOR THE DIAGNOSIS OF GROWTH-HORMONE DEFICIENCY

Evaluation of growth hormone (GH) secretion using pharmacological GH s timulation tests (GHSTs) remains current practice, although the reliab ility of GHSTs has been questioned and many pitfalls have been pointed out. We have analysed all the 6373 GHSTs which led to the initiation of GH therapy in 3233 children treated in France from 1973 to 1989. El even different pharmacological tests were used, and 62 out of the 66 t heoretical pairs of tests were used at least once. The most frequent c ombination of tests was used in 12.7% of patients. Reliability of GH p eak measured by comparing the results of two tests in the same patient was poor, as measured by intraclass correlation coefficients (all und er 0.8). Multivariate analysis identified several parameters positivel y or negatively associated with peak plasma GH. We believe that severa l of these factors (i.e. weight standard deviation score (SDS), geneti c target height SDS and nature of the agent) identify biases in the di agnosis of GH deficiency (GHD). In addition, we reevaluated GH secreti on in 208 young adults formerly treated with GH for childhood onset GH D. Peak plasma was superior or equal to 10 ng/ml in 81% of patients wi th former idiopathic GHD. We conclude that the current use of GHSTs as well as the criteria for idiopathic childhood GHD should be questione d. (C) 1998 Churchill Livingstone.