PLASMA-LEVELS OF INSULIN-LIKE-GROWTH-FACTOR (IGF)-I, IGF-II AND IGF-BINDING PROTEIN-3 IN THE EVALUATION OF CHILDHOOD GROWTH-HORMONE DEFICIENCY

Background: Traditionally, measurement of plasma IGF-I and more recent ly of IGFBP-3 are used to distinguish GHD from idiopathic short statur e in slowly growing children, using a single blood sample. In earlier studies it was claimed that IGFBP-3 was superior to IGF-I, but more re cently doubts around this claim have arisen. The role of serum IGF-II has never been studied extensively. On theoretical grounds, it can als o be hypothesized that molar ratios of these peptides might be of addi tional value. Design: Retrospective, multicentre, cohort study. Patien ts: 96 children evaluated for short stature. Methods: Serum IGF-I, IGF -II, IGFBP-3 and various molar ratios were, after correction for age a nd sex using SD scores, compared to the maximum serum GH peak after tw o standard provocation tests using four different methods (t-test, chi (2), likelihood ratios and ROC curves). In addition, the correlations between these parameters and the short-term(1 year) and long-term (3 y ears) response to GH therapy were calculated. Results: IGF-I performed better than IGFBP-3, but the best results were achieved by the molar ratio IGF-I:IGF-II. However, IGFBP-3 correlated better with the short- term response to CH therapy than IGF-I or the ratios, and none of the parameters investigated was found to be related to the response of lon g-term GPI therapy.