7795 Gender based differences in peripubertal growth patterns may offer insight into the twofold representation of boys compared to girls among children referred for growth hormone stimulation tests

Abstract Disclosure: Y. Dekel: None. L. Horowitz : None. R. Gendelman: None. M. Cohen: None. Background: Growth hormone (GH) stimulation tests are essential in the diagnostic assessment of pediatric GH deficiency (GHD). However, the tests bare multiple limitations, resulting from both intrinsic and child-related factors. Thus, referral decisions are key in making a correct diagnosis. Several studies demonstrated a gender bias in referral for short stature evaluation with a higher proportion of boys referred and diagnosed with GHD. Moreover, the boys had higher height z-scores upon referral. About 100 GH stimulation-tests are conducted annually at our pediatric endocrinology unit. We aimed to characterize the children that underwent GH stimulation-testing between 2017-2021, specifically focusing on differences based on: 1) gender 2) GH secretion status (deficient vs. sufficient). Methods: A retrospective review of charts of children aged 0-18 years that performed GH stimulation-tests at the Rambam pediatric endocrinology unit between the years 2017-2021 was conducted. Children followed at an outside clinic that had a first GH stimulation-test elsewhere, were excluded. Data was collected through the electronic database and by manually screening medical charts. The IBM SPSS statistics package 21 version was used for analysis. Results: Four-hundred children were included in the study, 266 boys (66.5%) and 134 girls (33.5%). Mean age 8.8±4.2 years, mean height z-score -2.3±0.7 and mean mid-parental height standard-deviation-scores (MPH-SDS) -0.6±0.7. The mean difference between MPH-SDS and child height-z-score was 1.7±0.8 SDS. Mean age was younger in girls compared with boys, 7.3±3.3 and 9.6±4.4 years respectively (p<0.001). Age distribution differed between genders, while refferals peaked between 3-4 years of age in both girls and boys, a second peak at 13-14 years of age was evident only in boys. Interestingly, there was no significant difference between boys and girls in height z-score, difference from MPH-SDS or rates of GHD. Overall, 93 (23.3%) children were diagnosed with GHD, 32 girls (24%) and 61 boys (23%). Children with GHD were younger and had higher BMI-SDSs compared to GH sufficient children, age 7.8±3.8, 9.2±4.3 years respectively (p=0.003), BMI z-score 0.17±1.38, -0.47±1.15 respectively (p<0.001). Conclusion: Twice as many boys than girls were referred for GH stimulation tests in our cohort. Based on differences in age distribution, the peripubertal physiologic growth deceleration that occurs later in boys, likely contributes to this finding. This male-to-female ratio is similar to ratios reported in the literature regarding short stature referrals; however, in contrast to the literature, in our cohort it could not be explained by an anthropometric bias in referral criteria. Presentation: 6/3/2024