medwireNews: A randomised trial shows that use of aromatase inhibitors enhances the growth of boys receiving growth hormone (GH) to treat severe idiopathic short stature (ISS).

The trial, conducted by Nelly Mauras (Nemours Children’s Health System, Jacksonville, Florida, USA) and colleagues, involved 76 pubertal boys with an average age of 14.1 years and height standard deviation score (SDS) of –2.3, without an identifiable cause.

During 24 months of treatment, boys randomly assigned to receive aromatase inhibitors alone gained 14.0 cm in height, but the height gain was significantly greater in those given GH, at 17.1 cm, and greater still in those given GH plus aromatase inhibitors, at 18.9 cm.

The researchers note that this “compares favorably” to the expected increase of 10.1 cm in boys of this age with a height SDS of –2.0.

Height SDS improved to –1.73, –1.43 and –1.25 in patients given aromatase inhibitors, GH and both treatments, respectively. Because aromatase inhibitors enhance growth by delaying epiphyseal fusion, patients given the treatment had slower bone age progression than those given just GH; the corresponding bone-age–corrected height SDSs were –1.06, –1.11 and –0.41.

The team describes the results as “remarkable”, considering the age and baseline height SDS of the patients. The near-final heights for patients given aromatase inhibitors, GH and both treatments fell short of their mid-parental heights by a respective 7.8, 5.3 and 4.5 cm.

“This likely overestimates the differences between near-final and target height as often we could not measure both parents’ heights, and adults often tend to overestimate their own height”, Mauras et al write in The Journal of Clinical Endocrinology & Metabolism.

“These results however underscore the positive impact of these growth-promoting therapies even when initiated in the midst of puberty.”

The patients’ height-adjusted bone mineral density z scores decreased during treatment in all groups, but remained within the normal range. The team also found no evidence of vertebral irregularities, despite these previously being reported in boys treated with letrozole. What mild baseline abnormalities they did detect often improved during treatment.

Use of aromatase inhibitors led to an increase in testosterone levels, which was most marked with letrozole, and was matched by a larger reduction in oestradiol.

By Eleanor McDermid

J Clin Endocrinol Metab 2016; Advance online publication

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