ESPE Abstracts

Background: Several definitions of poor growth response to first-year GH treatment, have been proposed based on the observed response of a large group of patients.

Objective and hypotheses: Since a complete compensation of the height deficit is expected in children with GH deficiency (GHD) treated with GH, we have studied the different parameters for the first-year growth response in relation to the adult height gain in prepubertal children with iGHD.

Method: Height data at start, after 1 year of GH treatment, and at near final adult height (nFAH) of 142 prepubertal children (93 boys) with GHD, were retrieved from the National Database of the Belgian Study Group for Pediatric Endocrinology. These patients had been treated with GH for at least 4 consecutive years with at least 1 year before pubertal onset. First-year change in height SDS (ΔHtSDS), first-year height velocity (HV) and total height SDS gain from start up to nFAH (total ΔHt SDS) were calculated. A poor final growth outcome was defined as total ΔHt <1 SDS.

Results: Mean (S.D.) nFAH SDS was −1.69±3.26, nFAH – midparental height SDS was −0.03±1.79, and total ΔHt SDS was 1.73±0.66. By ROC analysis first-year HV SD <0.70, and Δ HtSDS <0.3 are very sensitive criteria (96.8 and 96.6% sensitivity respectively) to predict a total gain in height SDS <1. The corresponding specificities are 20 and 23.1%. The area’s under the curve are respectively 77.1 and 79%. The accuracies of the tests are respectively 79.8 and 81.7%.

Conclusion: Our results confirm that a first-year change in height SDS <0.3 will detect almost all poor final height responders, but due to its low specificity it is not always associated with a poor final height outcome. Depending on the chosen sensitivity or specificity, different cut-offs for poor first-year response can be determined by ROC analysis.