Comparison of response to 2-years’ growth hormone treatment in children with isolated growth hormone deficiency, born small for gestational age, idiopathic short stature, or multiple pituitary hormone deficiency: combined results from two large observational studies

Analysis of auxologic data from two ongoing prospective observational studies, NordiNet？ International Outcomes Study (NordiNet？ IOS) and NovoNet？/American Norditropin？ Studies: Web-enabled Research (ANSWER) Program？.4,582 children aged <18？years were included: IGHD, n？=？3,298; SGA, n？=？678; ISS, n？=？334; and MPHD, n？=？272. After two years’ GH treatment, change in height standard deviation score (SDS) was +1.03 in SGA and +0.84 in ISS vs. +0.97 in IGHD (p？=？0.047; p？<？0.001 vs. IGHD, respectively). Height gain was comparable between IGHD and MPHD. In pre-pubertal children vs. total population, height SDS change after two years was: IGHD, +1.24 vs. +0.97; SGA, +1.17 vs. +1.03; ISS, +1.04 vs. +0.84; and MPHD, +1.16 vs. +0.99 (all p？<？0.001).After two years’ GH treatment, change in height SDS was greater in SGA and less in ISS, compared with IGHD; the discrepancy in responses may be due to the disease nature or confounders (i.e. age). Height SDS increase was greatest in pre-pubertal children, supporting early treatment initiation to optimize growth outcomes.