ESPE Abstracts

Background: Central precocious puberty (CPP) is a premature activation of the hypothalamic-pituitary-gonadal axis. One of its negative effects is lower final adult height (FAH) due to premature epiphyseal closure. GnRH analogues act by desensitizing GnRH receptors and stopping the progression of puberty and prolonging growth period.

Objectives: We aimed to evaluate the effect of the GnRH analogue on FAH and identify factors that predict FAH in children with CPP.

Population and Methods: A retrospective study included 93 children (12 boys and 81 girls) with CPP or menarche before 10 years, that reached their FAH (68 with idiopathic (iCPP) and 25 with an identified likely cause of CPP (nCPP)). Clinical characteristics including FAH between the two groups were compared. We also compared FAH between the children treated with triptorelin depo (n=71) and untreated children (n=22). Finally, to determine predicting factors for FAH, in 81 girls with CPP multiple regression analysis was conducted. Target height (TH) was calculated based on parental heights. Predicted adult height (PAH) was calculated based on bone age, chronological age, height at diagnosis and ethnicity with BoneXpert software.

Results: The children with iCPP reached significantly higher FAH than children with nCPP (P=0.002). Negative SDS of FAH in both groups indicated lower FAH in children with CPP as compared to the general population. There was no significant difference in the FAH between the treated and untreated children. However, the study was retrospective and the decision to initiate treatment was individualised and not randomised. Nonetheless, the treated group gained 31.2 cm since CPP diagnosis up to the FAH as compared to 23.7 cm in the untreated group, while at the diagnosis the treated group was younger (median 7.52 y [Q1= 6.59; Q3= 8.18] vs. 8.85 y [8.48;9.24]), had lower height and BMI SDS and less advanced bone age. Predicting factors for FAH revealed by multiple linear regression analysis were bone age at diagnosis, height at the end of treatment, TH SDS, PAH SDS, height at diagnosis SDS, BMI at diagnosis SDS, LH peak, age at initiation and at the end of treatment, and height at the end of treatment SDS (R2=0,74).

Conclusion: Children with nCPP reached lower FAH as compared to the iCPP group despite similar baseline characteristics. From CPP diagnosis, the treated children gained 7.5 cm more than the untreated; yet, the FAH was not different. Factors that influence FAH are numerous, and should be considered at individualized decision-making.