SUN-203 - Peak Growth Hormone Level during Growth Hormone Stimulation testing Does Not Correlate with First-Year Growth Velocity in Children with Growth Hormone Deficiency

Background
Pediatric growth hormone deficiency (GHD) is characterized by short stature, reduced growth velocity (GV), and delayed bone age. Growth hormone stimulation testing (GHST) remains the diagnostic gold standard but has notable limitations in sensitivity and specificity. This study evaluated whether the timing and/or value of peak growth hormone (GH) levels during GHST correlated with first-year GV response to GH therapy in the pediatric population, with the goal of informing clinician and patient treatment expectations for those with GHD.
Methods
This study consisted of a retrospective analysis of 213 patients aged 3–15 years diagnosed with GHD (peak GH < 10 ng/mL via clonidine/arginine GHST) between January 2020 and December 2022. Patients treated with GH for other indications or without ≥1 year of follow-up were excluded. Descriptive statistics and nonparametric tests were used (p < 0.01). Variables analyzed included, race, sex, age, midparental height, bone age with predicted adult height, and insulin like growth factor-1 level in relation to GHST parameters (peak GH level/timing), initial GH dose, and 1-year anthropometric outcomes. Artificial Intelligence tools were used for refinement of this abstract.
Results
First-year GV was not associated with peak or timing of peak GH level during GHST. No significant associations were found between GV and other anthropometric or biochemical measures, with the exception of a positive correlation with age and inverse correlations between peak GH and weight/body mass index (BMI).
Conclusion
In children meeting biochemical criteria for GHD, GHST parameters showed no association with first-year GV response to GH therapy. These findings suggest that commonly used diagnostic thresholds may not reliably reflect GH treatment responsiveness. Future studies are needed to determine if other factors such as nutritional or genetic influences may contribute more to their prediction of GH responsiveness. Further prospective studies incorporating a broader spectrum of potential correlative variables are warranted to fully elucidate determinants of GH treatment response. These results should inform anticipatory guidance and expectation setting when initiating GH therapy in pediatric GHD.

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