Children
The Effect of Body Mass Index on Peak Growth Hormone Response During Stimulation Testing: A Retrospective Analysis
By Eleonora Rulli, Marcello Candelli, Donato Rigante and 2 others.
Abstract
Background
Growth hormone (GH) stimulation testing remains the diagnostic gold standard for GH deficiency (GHD), but body mass index (BMI) inversely influences peak GH levels, creating a risk of overdiagnosis. We evaluated the association between BMI standard deviation score (SDS) and peak GH response in children undergoing diagnostic work-up for suspected GHD.
Methods
This is a retrospective single-center study of 298 children (55.4% male, mean age 9.5 ± 2.9 years) evaluated for growth failure with arginine or clonidine stimulation testing. GHD was confirmed in 114 patients (38.3%). Multivariable linear and logistic regression models evaluated associations after adjustment for age, sex, and pubertal status.
Results
BMI SDS negatively correlated with peak GH levels in the overall cohort (r = −0.299, p < 0.001) and in GHD patients (r = −0.322, p < 0.001), but not in non-GHD controls (r = −0.102, p = 0.167; Fisher’s z p = 0.050). On multivariable analysis, each 1-SDS increase in BMI SDS was independently associated with a 1.63 ng/mL reduction in peak GH (β = −1.63, 95% CI −2.20 to −1.07; p < 0.001) and 2.10-fold higher odds of GHD diagnosis (OR 2.10, 95% CI 1.60–2.74; p < 0.001). Across BMI SDS quartiles (Q1 to Q4), mean peak GH progressively decreased from 11.14 to 6.93 ng/mL (p < 0.0001), while GHD prevalence increased from 22.4% to 62.7% (p < 0.0001).