Don't Use Growth Hormone for Anti-Aging, Say New Guidelines

Marlene Busko

December 05, 2019

The 2019 Guidelines for Management of Growth Hormone Deficiency in Adults and Patients Transitioning from Pediatric to Adult Care issued by two key US endocrine societies cover important developments in the decade since the previous version.  

The full text, by Kevin C.J. Yuen, MD, and colleagues, is available online in Endocrine Practice.  

Among other topics, the guidelines discuss currently recommended diagnostic tests; growth hormone (GH) deficiency caused by reasons other than a pituitary tumor; long-term safety data; and importantly, they also stress that GH replacement therapy should never be used for age-related conditions or to enhance athletic performance, Yuen told Medscape Medical News

The document, by the American Association of Clinical Endocrinologists (AACE) and the American College of Endocrinology (ACE), "is a practical tool that practicing endocrinologists and regulatory bodies can refer to regarding the identification, diagnosis, and treatment of adults and patients transitioning from pediatric to adult care services with G deficiency," Yuen, medical director of both the Barrow Pituitary Center and the Barrow Neuroendocrinology Clinic, Phoenix, Arizona, and colleagues summarize.

The document is the first update for 10 years, although the Endocrine Society, published a similar document in 2011.

Accumulating Evidence of Benefits

Recombinant human GH (rhGH) replacement therapy first became commercially available in the United States in 1985, and "there is now accumulating evidence of its beneficial effects in reversing many but not all of the metabolic abnormalities associated with" adult GH deficiency, Yuen and colleagues write by way of background.

"Nonetheless, there is still some controversy in the United States regarding the appropriate use of rhGH therapy" in adults with GH deficiency arising from the high cost of rhGH therapy (about $18,000 to $30,000 a year), the need to administer daily injections, and concerns about potential adverse effects with long-term therapy, they note.

The guideline authors reviewed the most recent clinical evidence to develop these latest recommendations.

Identification, Diagnosis, and Treatment

Clinicians should consider that patients who have a history of hypothalamic–pituitary disease may have GH deficiency, the authors advise.

Children or adult "patients with pituitary tumors who have surgery and radiation make up the majority of patients who subsequently go on to develop growth hormone deficiency," Yuen said.

However, importantly, over the past decade there has been growing awareness of other causes of adult GH deficiency, he noted, such as traumatic brain injuries — for example, caused by playing contact sports (such as ice hockey, boxing, NFL football) or from combat in Iraq or Afghanistan — as well as subarachnoid hemorrhage, ischemic stroke, and infections of the nervous system.

The guidelines stress that clinicians can consider testing patients for whom there is a reasonable level of clinical suspicion of GH deficiency and they should use appropriate cut-points for the tests (which stimulate the production of GH by the pituitary gland).

The insulin tolerance test to stimulate GH secretion is still the gold standard to establish a diagnosis of GH deficiency, but if it is contraindicated or not feasible in a given patient, then the glucagon stimulation test or macimorelin (Macrilen in the United States, Novo Nordisk; Macimorelin in Europe, Aeterna Zentaris) stimulation test could be used.   

As reported by Medscape Medical News, the macimorelin stimulation test was approved by the US Food and Drug Administration in December 2017 and the European Medicines Agency in November 2018.

And when a patient is on rhGH replacement therapy, clinicians need to "exercise caution interpreting serum GH and insulin-like growth factor-1 (IGF-1) levels, as various GH and IGF-1 assays are used to support treatment decisions," the authors emphasize.

Long-Term Safety, New Agents on the Horizon

During the past decade there has been "increasing evidence of beneficial effects and long-term safety of GH replacement," Yuen said.

"Because growth hormone can make things grow," he added, clinicians may wonder if cancer and tumor regrowth are risk factors when prescribing growth hormone.

"The answer is no," he said.

"The [safety] evidence over the last 10 years has been extremely reassuring," he noted, including evidence of safety during pregnancy.  

"Finally, there is also a section on the status of long-acting growth hormone, which is not available yet but will be available in the next few years or so — a once-a-week injection," Yuen explained.

As reported by Medscape Medical News, researchers presented data from a phase 3 trial of the once-weekly GH derivative somapacitan (Novo Nordisk) and a dose-finding phase 2 safety study of the long-acting recombinant GH somavaratan (Versartis) in adults with GH deficiency at ENDO 2017: The Endocrine Society Annual Meeting.

Not for "Anti-Aging" or Athletic Performance

Yuen stressed that a physiologic decline in endogenous GH secretion is a normal part of aging.

So "one of the major reasons...we wanted to get this document out [was] to send a strong message" that growth hormone should not be used for anti-aging or to enhance sports performance, he emphasized.

"In the United States, off-label distribution or marketing of GH for the enhancement of athletic performance or to treat aging, or aging-related conditions, is illegal and punishable by imprisonment,” the guidelines warn.

“Under no circumstances should rhGH be prescribed for sports or for 'anti-aging' purposes," they stress.

Consistent With Other Guidelines, But More Up to Date

"The name 'growth hormone' is actually confusing," Yuen noted.

"People read about it and say, 'Why do I need growth hormone when I am already an adult?'" he said.

"They should change the name from growth hormone to somatotropin because GH is a very important hormone in adults," he emphasized.  

It affects "metabolism, bone function, brain function, fat deposition, and muscle development," he noted.

And "we know now that patients who are untreated for GH deficiency for many years are at high risk of developing obesity, diabetes, increased cardiovascular disease, and high cholesterol and dyslipidemia."

These new guidelines for adults with GH deficiency are generally consistent with those of the 2011 Endocrine Society recommendations, Yuen said, except that "we have also added all the new findings" from the past 8 years.

Endocr Pract. 2019;25:1191-1232. Full text

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