6729 Exploring the Body Composition of Pediatric Patients With Growth Hormone Deficiency and Idiopathic Short Stature Under RecombinantGH Treatment

Abstract Disclosure: H. Zaitoon: None. M. Yackobovitch-Gavan, PhD: None. E. Midlij: None. A. Uretzky: None. I. Laurian: None. A. Dorfman: None. H. Interator: None. Y. Lebenthal, MD: None. A. Brener: None. Background: Growth hormone (GH) is an anabolic hormone that stimulates protein accretion in skeletal muscle. Treatment for growth hormone deficiency (GHD) and idiopathic short stature (ISS) in children and adolescents by means of recombinant human growth hormone (rGH) is mainly aimed at linear growth augmentation, while its impact on body composition remains obscure. Methods: This retrospective observational study included 305 bioimpedance analysis (BIA) reports of pediatric patients with GHD and those with ISS whose clinical data were extracted from medical records. Generalized estimating equations linear models were used to explore the contributing factors for body composition components of the appendicular skeletal muscle mass (ASMM) and the muscle-to-fat ratio (MFR) z-scores while adjusting for cumulative doses of rGH. Results: Of the 135 pediatric patients enrolled in the study, 89 (65.9%) were boys. This group included 64 patients diagnosed with GHD and 71 with ISS. Those with GHD exhibited significantly higher body mass index z-scores (p<0.001), higher fat percentages (FATP), higher truncal FATP scores, lower MFR z-scores, and higher diastolic blood pressure percentiles than the ISS group (p=0.010, p=0.027, p=0.050, and p=0.050, respectively). Female sex (p=0.049) and ISS diagnosis (p=0.005) were major contributors to higher MFR z-scores, while female sex (p<0.001), older age (p<0.001), and higher insulin-like growth factor 1 (IGF1) z-scores (p=0.021) were major contributors to higher ASMM z-scores. Socioeconomic position and cumulative rGH dose did not significantly contribute to body composition parameters. Conclusion: This study demonstrated an inclination towards increased adiposity in young individuals with GHD compared to those with ISS, while the muscle component remained unaffected. Considering the influence of IGF1 on the regulation of muscle mass, treating GHD with rGH with the aim of attaining normal IGF1 levels could temper the elevated adiposity in affected patients. Presentation: 6/3/2024