SUN-173 Hormone Replacement Therapy in Youth with Turner Syndrome: Retrospective Multicenter Review

Abstract Disclosure: A.P. López López: None. T. Dowlut-McElroy: None. A. Magaldino: None. K. Verma: None. L.L. Levitsky: None. M. Misra: None. R. Kanakatti Shankar: RKS has received research funding from BioMarin Pharmaceutical Inc., is a consultant for BioMarin, with fee paid to her institution, Children's National Hospital. Turner syndrome (TS) is associated with primary ovarian insufficiency in a majority of individuals and hormone replacement therapy (HRT) is vital for cardiometabolic health. However, the optimal dose and route of estrogen and the type of progestin for HRT in adolescents and young adults (AYA) with TS, especially after pubertal induction, are not clearly established. We reviewed HRT use in a multicenter retrospective cross-sectional study to explore the impact on cardiometabolic factors.With IRB approval, data on HRT, anthropometrics, systolic (SBP) and diastolic (DBP) blood pressure, lipid profile, transaminases and glycated hemoglobin A1c (HbA1c) were abstracted from the most recent visit in post-pubertal girls with TS (ages 14- 25y) who had attained menarche by 1/1/2023 and were seen at one of 3 different institutions. Descriptive statistics were analyzed with JMP (v18) and one-way ANOVA or Kruskal Wallis tests were used for comparison between groups based on distribution, with significance set at p<0.05.Mean age of the cohort (N=133) was 17.9+/-2.5years with weight 60.4+/-15.4 kg, height 150.5+/-6.8 cm and body mass index (BMI) of 26.8+/-6.3 kg/m2; SBP and DBP were 117+/-11 and 73+/-9 mmHg respectively. Median (IQR) for total cholesterol was 166 (51), triglycerides 88 (63), HDL and LDL cholesterol were 56 (22) and 86 (36) mg/dL, with ALT 23 (11.5), AST 23 (11) IU/mL and HbA1c of 5.2 (0.4) %. HRT was not used in 24 (18%) and all 24 had a history of spontaneous menarche. Transdermal estradiol (TDE) was used in 57 (43%), oral estradiol in 10 (7.5%), combined ethinyl estradiol/progestin patch in 7 (5%), conjugated estrogen in one and 34 (25.5%) were on oral combined hormonal contraceptives (OCP). Progestins used were micronized progesterone in 27 (20%), medroxyprogesterone in 35 (26%), levonorgestrel intrauterine device in 3 (2%), other (e.g. aygestin, norelgestromin in a combined patch) in 10 (7.5%), no progestin in 24 (18%) and OCPs with different progestin combinations in 34 (25.6%). Between group comparisons showed that BMI was higher in the OCP group vs TDE and ‘no HRT’ and remained significant even after adjustment for age (p=0.03). SBP (p=0.04), total cholesterol (p=0.02) and triglycerides (p=0.03) were significantly higher in the OCP group but after adjusting for age, only triglycerides were significant (p=0.04). In comparing progestin types used with TDE, medroxyprogesterone was associated with higher BMI (p=0.03) and HbA1c (p=0.03) compared with micronized progesterone.There is considerable variation in estrogen/progestin type, route and dose used for HRT in AYA with TS after pubertal induction. Oral contraceptive use may be associated with higher BMI and triglycerides while medroxyprogesterone use may be associated with higher BMI and HbA1c. Prospective studies on cardiometabolic outcomes are needed to determine the optimal HRT in these individuals. Presentation: Sunday, July 13, 2025