ESPE Abstracts

Background: Prader-Willi syndrome (PWS) is a rare multisystemic genetic disorder. Recombinant human growth hormone (rhGH) therapy is the most established form of treatment for PWS. This study aimed to investigate the effect of rhGH treatment age on the treatment outcome of children with PWS.

Methods: A retrospective analysis of 167 genetically confirmed Chinese children with PWS followed between 2017 and 2022. Unadjusted and adjusted generalized estimating equations (GEE) were used to study the long-term trends in anthropometric parameters, insulin-like growth factor-1 (IGF-1), and glucose metabolism parameters during rhGH treatment in PWS. To compare the incidence of hypothyroidism, hip dysplasia, and scoliosis before and after rhGH treatment.

Results: The cohort had a significant increase in height/length standard deviation score (SDS). Compared to the infant group, there was an increase in height/length SDS by 0.42 (P =0.045) and body mass index (BMI) SDS by 1.80 (P =0.037) in the preschool group at year 3 and an increase in weight SDS by 1.09 (P =0.037) and BMI SDS by 1.91 (P =0.008) in the toddler group at year 3. BMI SDS remained stable in the school-age group. IGF-1 was consistently lower in the infant group than in the other groups over time (P <0.05). Both fasting insulin (FINS) and homeostasis model assessment of insulin resistance (HOMA-IR) increased significantly in the school-age group compared to the infant group (P <0.001). The incidence of hypothyroidism was increased in the cohort (P <0.05), independent of treatment age (P >0.05).

Conclusions: rhGH is effective in improving height/length SDS in children with PWS, especially in preschool, as well as weight and BMI-SDS in infancy and toddlerhood. rhGH appears to maintain a stable BMI-SDS in PWS long after school age. It is important to pay attention to changes in HOMA-IR during rhGH treatment. Further monitoring of high IGF-1 levels in older PWS is needed. Watch for hypothyroidism, which is often found in PWS infants, and further investigate whether it is related to long-term rhGH treatment.