Growth Hormone Dose-Dependent Pubertal Growth: A Randomized Trial in Short Children with Low Growth Hormone Secretion

Background/Aims: Growth hormone (GH) treatment regimens do not account for the pubertal increase in endogenous GH secretion. This study assessed whether increasing the GH dose and/or frequency of administration improves pubertal height gain and adult height (AH) in children with low GH secretion during stimulation tests, i.e. idiopathic isolated GH deficiency. Methods: A multicenter, randomized, clinical trial (No. 88-177) followed 111 children (96 boys) at study start from onset of puberty to AH who had received GH 33 µg/kg/day for ≥1 year. They were randomized to receive 67 µg/kg/day (GH67) given as one (GH67×1; n = 35) or two daily injections (GH33×2; n = 36), or to remain on a single 33 µg/kg/day dose (GH33×1; n = 40). Growth was assessed as heightSDSgain for prepubertal, pubertal and total periods, as well as AHSDS versus the population and the midparental height. Results: Pubertal heightSDSgain was greater for patients receiving a high dose (GH67, 0.73) than a low dose (GH33×1, 0.41, p < 0.05). AHSDS was greater on GH67 (GH67×1, -0.84; GH33×2, -0.83) than GH33 (-1.25, p < 0.05), and heightSDSgain was greater on GH67 than GH33 (2.04 and 1.56, respectively; p < 0.01). All groups reached their target heightSDS. Conclusion: Pubertal heightSDSgain and AHSDS were dose dependent, with greater growth being observed for the GH67 than the GH33 randomization group; however, there were no differences between the once- and twice-daily GH67 regimens.