Evolution of IGF-1 in Children Born Small for Gestational Age and with Growth Retardation, Treated by Growth Hormone Adapted to IGF-1 Levels after 1 Year

AIM: This study was designed to estimate the percentage of growth hormone (GH)-treated children born small for gestational age (SGA), with serum IGF-1 >2 SDS before and after GH dose adaptation. METHODS: SGA boys aged 4-9 and girls aged 4-7 with a height <-2 SDS and an annual growth rate below the mean received a subcutaneous GH dose of 57 μg/kg/day for 2 years. The GH dose was to be decreased by 30% in children with serum IGF-1 >2 SDS at 12 months and on the previous sample. The GH dose could be reduced a second time to 35 μg/kg·day. IGF-1 and IGFBP-3 dosages were centralized. RESULTS: Among the 49 (21 boys) children included in the study, 8 (16.3%) had an IGF-1 >2 SDS consecutively at 9 and 12 months (95% CI 7.3, 29.7). The GH dose was decreased in 6/8 children. However, IGF-1 levels were elevated at several nonconsecutive determinations in 45% (95% CI 28.4, 56.6) of the patients. CONCLUSION: A high IGF-1 level is observed in 45% of the GH SGA-treated children with a relatively high dose of GH. A 30% reduction in the GH dose causes a decrease in IGF-1 below 2 SDS in most children.