In childhood an appropriate response to GH treatment is achieved by titration of growth response against dose administered, with careful observation for side-effects. In order to evaluate the potential use of IGF monitoring in children treated with GH, a cross-sectional study has been carried in 215 children and adolescents (134 with GH deficiency, 54 with Turner syndrome and 29 with non-GHD growth disorders) treated with GH for 0.2 to 13.7 years.
IGF-I and IGFBP-3 were measured in ELISAs, using dried capillary blood collected onto filter papers. Results were expressed as SD scores, <-2 or <+2 sds being considered abnormal. 19% of the IGF-I results (13% low, 6% high) and 12% of IGFBP-3 values were abnormal (10% low, 2% high). Satisfactory growth performance (+0.5>change in height sds>-0.5) was found in those with high (7.2%), normal (60%) and low (9.3%) IGF-I levels. However overall it was estimated that 26% of the tests would indicate that an adjustment to GH dose (up in 18% and down in 8%) could be considered.
In the GHD and non-GHD groups, [IGF-I - IGFBP-3] sds, as a measure of the discrepancy between IGF-I and its principal carrier protein, was a significant positive factor rather than IGF-I sds alone for change in height sds over the year up to the sample.
This work has indicated that (1) the majority of children on GH have normal levels of IGF-I and IGFBP-3, (2) 26% of tests could lead to GH dose adjustment, (3) levels of IGF-I and IGFBP-3 in dried blood spots are a convenient and relevant measurement, and (4) [IGF-I - IGFBP-3] sds is a better marker of growth performance than IGF-I alone. Regular monitoring of IGF-I and IGFBP-3 should be considered in childhood GHD.
08 - 11 Apr 2002
British Endocrine Societies