Growth Hormone Therapy Appears Safe and Helpful for PWS Adults

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by Joana Carvalho |

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Growth hormone therapy, a common treatment for children with Prader-Willi syndrome (PWS),  is also safe and effective at increasing lean muscle mass and lowering body fat in adults with this disease, a review study reports.

More work is needed, however, to confirm the therapy’s effects on body composition, as well as to clarify its possible impact on bone and cardiovascular (heart and blood vessels) health in these patients, its researchers said.

The study, “The use of growth hormone therapy in adults with Prader‐Willi syndrome: A systematic review,” was published in the journal Clinical Endocrinology.

PWS is caused by the loss of a set of paternal genes located on chromosome 15 that are known to control metabolism, appetite, growth, intellectual ability, and social behavior.

Without these genes, patients have little control over the amount of food they eat, gaining weight to an extent that includes obesity. And they are at risk of obesity’s known complications, such as heart disease, diabetes, and high blood pressure.

A shift in body composition, the loss of lean muscle mass and subsequent increase in body fat, are also hallmarks of PWS in children.

Growth hormone (GH) therapy is used to counteract this disease’s effects in children. This form of treatment not only promotes growth, but also helps restore a balance between lean muscle and body fat in young patients. By increasing the amount of lean muscle mass, it also may contribute to better muscle function and motor abilities.

Its potential health benefits in adults are unclear, however, as this treatment is not currently licensed for those 18 or older, except in cases of GH deficiency.

Researchers at the University of Glasgow conducted a systematic review to summarize data from studies into the effects GH therapy might have on adult body composition, bone, and the cardiovascular health.

Using PubMed, a large online database, the investigators looked for studies, published between 1960 and March 2020, of GH therapy’s use in individuals ages 16 or older with a confirmed genetic diagnosis of PWS. Eligible studies focused on evaluating the therapy in those three area: body composition, bone, or cardiovascular health. Two scientists independently reviewed the relevance of those identified in this search.

A total of 20 studies covering 364 patients, ages 17–42, were ultimately selected. GH was given at doses ranging from 0.5 mg to 1.0 mg daily, and treatment lasted between six months and five years. Patients were followed for one to six years, depending on the study.

Nearly all studies (90%) assessed how GH therapy affected patients’ body composition, while far fewer included evaluations of cardiovascular (40%) and bone (25%) health.

Analyses regarding body composition found older patients on GH therapy in these studies tended to see their lean muscle mass increase and their body fat decrease. Two studies suggested that gains in lean muscle were accompanied by greater muscle strength and function.

For cholesterol levels, treatment seemed  to be inconsistent in its effects, but significant benefits were found in heart health. No studies of GH therapy reported significant changes on adult patients’ blood pressure.

Significant changes were also not seen on bone mineral density with this treatment, but one study reported an improvement in bone size and strength with its use.

A total of seven studies noted side effects, all considered minor. Swelling, especially in the lower legs in the first month of treatment, was the most common. Headaches, nausea, and impaired glucose tolerance were also observed in some patients
“The data from the 20 studies included in this systematic review suggest that GH therapy in adults with PWS is likely to result in favourable outcomes, particularly with regard to body composition,” the researchers wrote.
With no major side effects evident, these investigators considered GH therapy to be safe for adults with PWS. They recommended its use in these patients, “supported by a multidisciplinary team to monitor their progress and record any side effects.”
But for its use in these adults, “further longitudinal studies are still required to investigate the effects of GH on bone and cardiovascular health,” the researchers added.