8517 Low Peak GH in Stimulation Tests Among Obese Children; Is it Clinically Meaningful?

Abstract Disclosure: D. Strich: None. C. Meirman: None. S. Edri: None. D.J. Gillis: None. Background: Peak growth hormone (GH) levels in stimulation tests are lower in obese subjects. The clinical significance of this finding is unclear. It has been suggested that results of tests should be adjusted for body mass index (BMI). Aims: A. To evaluate the association between GH peak levels and body mass index (BMI ) in a single center. B. To discuss the biological and clinical significance of the findings and make recommendations based on this study and other data from the medical literature. Methods: Peak GH levels and BMI standard deviation scores (BMI-SDS) for a total of 988 tests (Clonidine - 694, Glucagon - 198, Arginine - 96) performed in one center were analyzed. Studies referring to the biology of growth hormone and to the evaluation of GH deficiency were reviewed. Results: In the testing center studied, mean peak GH levels were significantly lower in arginine (p=0.015) and clonidine tests (p=0.018) starting at BMI standard deviation score over 1 compared to below 1 BMI-SDS. The differences still remained significant for a subgroup with peaks below 7.5 ng/dl (p=0.003 and p=0.042 respectively). The proportion of overweight and obese children in our cohort and in similar cohorts of children undergoing stimulation tests was about tenfold lower than in the corresponding general population. In other studies, short obese patients responded better than non-obese to GH treatment and had greater increases both in height and IGF-1. Obese adult patients with low GH peaks had high carotid intima-media thickness compared with non GH deficient obese. Conclusion: Obese children are generally tall and therefore are not referred for testing. Those who are short, tend to have lower peaks than their lean peers in GH stimulation tests and respond better to GH therapy. These patients have biologically significant GH deficiency. We do not recommend "correcting" GH test results for BMI in the decision algorithm for GH therapy. Presentation: 6/3/2024