medwireNews: Treatment with recombinant human growth hormone (rhGH) results in an increased final adult height in children with molecularly confirmed Silver–Russell syndrome (SRS), as well as an improved BMI that persists after treatment cessation, say researchers.
The retrospective study compared long-term outcomes of 55 SRS patients who received rhGH treatment as children and 16 who did not. The patients were treated at centres in the UK, Germany and France, and were aged between 13 and 70 years (median 22 years) at the time of the analysis.
Justin Davies (University of Southampton, UK) and co-researchers stress that all their patients had their diagnosis confirmed by genetic testing, whereas previous studies relied at least partly on clinical diagnostic criteria for SRS, so may have included conditions with similar clinical features.
“Previous findings may thus not truly reflect the growth outcomes of molecularly confirmed cases of SRS and as we move to an era of personalized medicine, epigenotype-phenotype correlations are increasingly relevant”, they write in Clinical Endocrinology.
In this study, the untreated group had a median height standard deviation score (SDS) of –2.91 at a median age of 2.7 years, and this improved by only 0.53, to an adult height SDS of –2.74.
The rhGH-treated group had a median height SDS of –3.46 at a median age of 4.1 years. They received rhGH for a median of 7.1 years, resulting in a median height SDS gain of 1.53 to give a final adult height SDS of –2.22.
Thirteen patients started treatment before the age of 4 years. They had a larger initial height deficit than patients who started treatment later, at a median SDS of –5.26 versus –2.98, but gained more height during treatment, at a median of 3.13 versus 1.42 SDS.
This suggests “that early treatment initiation should be considered in SRS”, say the study authors.
In addition to improved height, the rhGH-treated group had BMIs closer to normal values at follow-up. At the age of 3–4 years, median BMI was similar in the treated and untreated groups, at −2.65 and −2.78, respectively.
BMI SDS then increased by a median of 2.01 in treated patients versus 3.58 in untreated patients, to reach a most recent value of –1.10 versus 1.66. Fewer than 2% of the treated patients had a BMI SDS of 2.0 or higher, compared with 25% of the untreated group.
“The finding of lower BMI in association with GH treatment is novel and we speculate that treatment may influence a more positive long-term metabolic outcome”, say the researchers.
They add: “We speculate that lower BMI results from differences in body composition including reduced fat mass in GH-treated individuals. GH-treated individuals may have been more physically active in childhood as a result of their treatment and may have developed beneficial exercise habits that continued into later life.”
By Eleanor McDermid
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