medwireNews: US researchers report “positive” experiences with growth hormone (GH) therapy in children with idiopathic short stature (ISS).

However, they found a noticeable difference in treatment response between children with familial and nonfamilial short stature, with children whose height was at odds with their parents’ making greater gains, on average. The researchers included children with peak GH greater than 7 ng/mL, as opposed to greater than 10 ng/mL as in many previous studies.

Juan Sotos and Naomi Tokar, from Nationwide Children’s Hospital in Columbus, Ohio, reviewed data for 88 children with ISS treated with GH, having excluded 27 who were lost to follow-up and eight who were also treated for delayed puberty. The children were about 12 years old, on average, at the start of treatment and received a higher average dose than used in many previous studies, of 0.32 mg/kg per week.

At baseline, the children’s average height standard deviation score (SDS) was –2.61, whereas their target adult height SDS, based on their parents’ height, was –0.61. Their final adult height SDS was –0.71, meaning they gained an average of +1.90 SDS, although this ranged from +0.29 to +4.13 SDS.

By comparison, 305 untreated patients with ISS in historical studies attained an average adult height SDS of –2.16, say Sotos and Tokar. However, they stress that there was wide variation in the height gain among the children in their study, and that “averages are not accurate or useful to predict the benefit that an individual will obtain.”

Age and puberty did not appear to influence treatment success, but there was a clear difference between children with familial and nonfamilial short stature. The 63 children with nonfamilial short stature had a baseline height SDS of –2.62 and attained an SDS of –0.56 for a gain of +2.06 (range; +0.94–3.90). The 25 children with familial short stature had significantly smaller gains, with corresponding SDSs of –2.59, –1.08 and +1.51 (range; +0.29–2.40).

The researchers note that the average height gains in their patients were similar to those reported in other studies using at least 0.3 mg/kg per week GH, and about 5 to 6 cm more than those achieved in studies that used lower doses.

“There have been, probably, enough trials with a dose of less than 0.3 mg/kg/week to know that it is not an adequate dose to induce a meaningful or satisfactory gain”, they write in the International Journal of Pediatric Endocrinology. They add that additional trials using higher doses “would be helpful.”

By Eleanor McDermid, Senior medwireNews Reporter

Int J Pediatr Endocrinol 2014; 2014: 15

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