ESPE Abstracts

Objective: To evaluate the improvement of Final Adult Height FAH) in adolescent idiopathic short stature boys treated with third-generation aromatase inhibitors (AI), letrozole and anastrozole combined with growth hormone, and to compare the efficacy and safety of long-term treatment with letrozole and anastrozole in childhood.

Method: This study collected data from 105 adolescent boys with idiopathic short stature (ISS) and large bone age (bone age ≥13 years) who were treated at the Department of Pediatrics Tongji Hospital from 2017 and 2023. Among 105 patients, there were 40 cases in the letrozole combined with rhGH group, 35 cases in the anastrozole combined with rhGH group, and 30 cases in the GnRHa combined with rhGH group. The treatment period was more than 18 months, and follow-up was conducted every 3 months until Final Adult Height FAH. Adverse events were also monitored throughout the study.

Results: In terms of bone age control, the total bone age difference/chronological age difference Δ BA/ Δ CA) during the treatment period of rhGH combined with AI group was significantly lower than the GnRHa group (t=-5.5, P <0.01). The total ΔBA / ΔCA in the letrozole group (0.42 ± 0.04) was lower than that in the anastrozole group (0.57 ± 0.21); For the improvement of final adult height, the standard deviation score of final adult height adjusted for genetic target height FAHSDSTHt）in letrozole group, anastrozole group and GnRHa group were 0.57 ± 0.32, 0.89 ± 0.40 and 0.37 ± 0.10, respectively. Compared with letrozole and GnRHa, anastrazole combined with rhGH group showed the most significant improvement in adult height (t=-3.0 and -6.6, both P <0.01); After 18 months of AI combined with rhGH treatment, the testicular volumes and serum testerone levels of patients increased significantly. Compared with the anastrozole group, the estradiol concentration in the letrozole group was lower and the difference was statistically significant (P <0.05); 45.3% (34/75) presented with clinical manifestations of hyperandrogenism (increased body hair, rough and greasy face, severe acne, irritability), 58.6% (44/75) developed hyperuricemia, 42.6% (32/75) experienced a decrease in high-density lipoprotein (HDL), 25.3% (19/75) had sleep issues (either drowsiness or difficulty falling asleep) and memory decline,0.9% (7/75) of the children experienced joint pain. After termination of treatment, the abnormal monitoring indicators gradually returned to normal.

Conclusion: AI combined with rhGH effectively improved the PAH of these patients. Anastrozole has shown more significant effects in improving predicted adult height (PAH) with fewer adverse reactions, which was better than letrozole.