Factors Affecting Growth Velocity during Gonadotropin-Releasing Hormone Agonist Treatment in Girls with Idiopathic Central Precocious Puberty

ABSTRACT

PURPOSE: In some girls with central precocious puberty (CPP), growth velocity (GV) decreases below the age-appropriate normal range during gonadotropin-releasing hormone agonist (GnRHa) treatment. The purpose of this study was to investigate clinical and laboratory factors related to changes in GV during GnRHa treatment in girls with CPP. METHODS: We analyzed clinical and laboratory data of 49 girls (aged 7.8+/-0.5 years) with idiopathic CPP who were treated with GnRHa. GV, height standard deviation score (SDS), hormonal parameters, pubertal stage, chronological age and bone age (BA) were evaluated. RESULTS: GV during the first year of GnRHa treatment was 5.9+/-1.0 cm/yr and decreased significantly to 5.4+/-1.1 cm/yr during the second year of treatment (P = 0.005). GV during the third year (5.0+/-1.0 cm/yr) was not different from GV during the second year. During the second year of treatment, 8.2% and 36.7% of the girls had a GV or = 11 yr) at 1 year (55.6% vs. 19.4%; odds ratio [OR], 5.2; P = 0.022). In multivariate logistic regression analysis, more advanced BA at 1 year (OR, 6.1; 95% confidence interval [CI], 1.57-23.87) and lower height SDS for BA at 1 year (OR, 0.24; 95% CI, 0.06-0.94) were associated with relatively decreased GV (< 5 cm/yr) during the second year of GnRHa treatment. CONCLUSION: GV during and after the second year of GnRHa treatment in girls with idiopathic CPP remains within the normal prepubertal range, and relatively low GV during GnRHa treatment is associated with more advanced BA and lower height SDS for BA.