Increased final height in precocious puberty after long-term treatment with LHRH agonists: The National Institutes of Health Experience

We report 98 children who have reached final adult height in a long-term tr ial of LHRH agonist treatment. These children were 5.3 +/- 2.1 yr old at th e start of treatment and were treated with either deslorelin (4 mug/kg.d sc ) or histrelin (4-10 mug/kg.d) for an average of 6.1 +/- 2.5 yr. Final height averaged 159.8 +/- 7.6 cm in the 80 girls, which was significa ntly greater than pretreatment predicted height (149.3 +/- 9.6 cm) but stil l significantly less than midparental height (MPH) (163.7 +/- 5.6). Final h eight averaged 171.1 +/- 8.7 cm in the 18 boys, which was significantly gre ater than pretreatment predicted height (156.1 +/- 14.2 cm) but still signi ficantly less than MPH (178.3 +/- 5.2 cm). However, the average adult heigh t of the 54 children who had less than a 2-yr delay in the onset of treatme nt was not significantly different from their MPH, and 21 children exceeded MPH. Final height SD score correlated positively with duration of treatmen t (P < 0.01), midparental height (P < 0.001), predicted height at the start of treatment (P < 0.001), and growth velocity during the last year of trea tment (P < 0.001) and correlated inversely with delay in the onset of treat ment (P < 0.001), age at the start of treatment (P < 0.001), bone age at th e start of treatment (P < 0.001), bone age at the end of treatment (P < 0.0 01), breast stage at the start of treatment (P = 0.02), and bone age minus chronological age at the start of treatment (P = 0.001). We conclude that LHRH agonist treatment improves the final height for child ren with rapidly progressing precocious puberty treated before the age of 8 yr for girls or 9 yr for boys. Less delay in the onset of treatment, longe r duration of treatment, and lower chronological and bone age at the onset of treatment all lead to greater final height. All children with onset of p ubertal symptoms before age 8 in girls and age 9 in boys should be evaluate d for possible treatment. Treatment is appropriate in children with rapidly progressing puberty, accelerated bone maturation, and compromise of adult height prediction, regardless of bone age or chronological age at time of e valuation. However, once treatment is considered appropriate, it should be initiated quickly, because longer delays lead to shorter final height. In a ddition, the longer the treatment is continued, the greater is the final he ight outcome.