Adult height in girls with central precocious puberty treated with gonadotropin-releasing hormone analogues and growth hormone

GnRH analogues (GnRHa) represent the treatment of choice in central precoci ous puberty (CPP), because arresting pubertal development and reducing eith er growth velocity (GV) or bone maturation (BA) should improve adult height . However, in some patients, GV decrease is so remarkable that it impairs p redicted adult height (PAH); and therefore, the addition of GH is suggested . Out of twenty subjects with idiopathic CPP (treated with GnRHa depot-trip torelin, at a dose of 100 mu g/kg im every 21 days, for at least 2-3 yr), w hose GV fall below the 25th percentile for chronological age, 10 received, in addition to GnRHa, GH at a dose of 0.3 mg/kg week sc, 6 days weekly, for 2-4 yr; and 10 matched for BA, chronological age, and duration of GnRHa tr eatment, who showed the same growth pattern but refused GH treatment, serve d to evaluate the efficacy of GH addition. No patient showed classical GH d eficiency. Both groups discontinued treatment at a comparable BA (mean +/- SEM): 13.2 +/- 0.2 in GnRHa plus GH us. 13.0 +/- 0.1 yr in the control grou p. At the conclusion of the study, all the patients had achieved adult heig ht. Adult height was considered to be attained when the growth during the p receding year was less than 1 cm, with a BA of over 15 yr. Patients of the group treated with GH plus GnRHa showed an adult height significantly highe r (P < 0.001) than pretreatment PAH (160.6 +/- 1.3 us. 152.7 +/- 1.7 cm). T arget height (TH) was significantly exceeded. The group treated with GnRH a lone reached an adult height not significantly higher than pretreatment PAH (157.1 +/- 2.5 vs. 155.5 +/- 1.9 cm). TH was just reached hut not signific antly exceeded. The gain in centimeters obtained, calculated between pretre atment PAH and final height, was 7.9 +/- 1.1 cm in patients treated with GH combined with GnRHa; whereas in patients treated with GnRHa alone, the gai n was just 1.6 +/- 1.2 cm (P = 0.001). Furthermore, no side effects have be en observed either on bone age progression or ovarian cyst appearance and t he gynecological follow-up in the OH-treated patients (in comparison with t hose treated with GnRHa alone). In conclusion, a gain of 1.9 cm in adult he ight represents a significant improvement, which justifies the addition of GH for 2-3 yr during the conventional treatment with GnRHa, especially in p atients with CPP, and a decrease in GV so marked as to impair PAH, not allo wing it to reach even the third centile.