Do patients with idiopathic short stature or partial growth hormone deficiency need to continue growth hormone therapy during puberty?

OBJECTIVES

Growth hormone (GH) therapy in children with idiopathic short stature (ISS) and partial GH deficiency increases adult height. However, the benefit of continuing GH therapy through puberty is unclear. We aimed to assess whether GH therapy improves adult height compared to predicted adult height (PAH) at puberty onset.

METHODS

We performed a multicenter retrospective chart review of patients with ISS and partial GH deficiency. GH therapy began before or at the onset of puberty and continued until height velocity was <2.5 cm/year. Bone age and PAH at different treatment time points were collected.

RESULTS

About 60 % of the 72 patients started GH before puberty. The mean duration of GH therapy was 3.5 years in girls and 4.6 years in boys. The mean PAH gain from GH start to puberty onset was 8 cm for boys (p<0.01) and 3.1 cm for girls (p<0.01). The mean difference between near adult height and PAH at puberty onset (ΔHDP) was -0.62 cm (p=0.75) for boys and 1.82 cm for girls (p=0.07). A higher bone age to chronological age ratio at therapy start (p<0.01), higher body mass index standard deviation score (SDS) at therapy start (p<0.05), higher mid-parental height (p<0.05), and longer duration of pubertal GH therapy (p<0.05) were associated with a greater ΔHDP, whereas a higher height SDS at the onset of puberty (p<0.01) and a higher IGF-1 SDS at therapy start (p<0.01) were associated with a smaller increase. Peak GH levels and sex were not statistically significant predictors. The average cost for the final year of GH therapy was $122,000.

CONCLUSIONS

While GH therapy before puberty increases PAH, continuing treatment through puberty did not, on average, yield further height benefit and was costly. Physicians might consider whether to continue GH therapy once a child appears to have reached an adequate PAH.