Initial growth deceleration during GnRH analogue therapy for precocious puberty

OBJECTIVES: To compare the efficacy of goserelin and leuprolide on initial deceleration of growth and weight gain during the first 12 months of GnRH analogue treatment for precocious puberty. DESIGN: Retrospective cohort analysis. PATIENTS: Forty children with precocious puberty treated with either goserelin or leuprolide (33 females, mean age 7.3 and 7.7 years, respectively, at the start of treatment). MEASUREMENTS: The primary outcomes were baseline-to-6-months and 6-months-to-12-months change in height standard deviation score (SDS) and body mass index (BMI). Relative tall stature was calculated as the difference between height SDS and mid-parental height (MPH) SDS at baseline. RESULTS: Goserelin and leuprolide were associated with similar suppression of serum LH during the first 12 months of treatment (P = 0.62). Greater relative tall stature was strongly associated with more advanced bone age, greater BMI SDS and with greater reduction in height SDS in the first 6 months. Adjusted for relative tall stature, goserelin therapy was associated with significantly greater suppression of growth than leuprolide (P = 0.025) in the first 6 months of treatment, with no subsequent change in the second 6 months. A similar, significant increase in BMI was seen with both analogues. CONCLUSIONS: Both GnRH analogues were associated with effective biochemical suppression of puberty; however, goserelin was more effective at reducing linear growth during the first 6 months. Relative tall stature was a major determinant of the initial response to treatment.