The American Association of Clinical Endocrinologists
recently released
updated medical guidelines for the indications, diagnosis and
clinical use of growth hormone therapy in patients with growth hormone
deficiency in transition periods and in adulthood.
The AACE Board of Directors called for an update to the
2003 guidelines in light of recent advancements in the understanding of GH
therapy benefits and because of concerns about the unethical use of GH therapy
for sports and antiaging purposes.
“These guidelines are the result of recent
advancements in our understanding of the benefits of GH replacement for
patients,” David Cook, MD, FACE, interim division chief of
endocrinology at the Oregon Health & Science University and co-author of
the new guidelines, said in a press release.
The updated guidelines also provide new cut points for
stimulation testing of GH deficiency. “If the cut point is five and the
highest response is four, then the patient is GH deficient,” Cook said.
“Some tests also depend on BMI, such as the arginine + GH-releasing
hormone stimulation test.”
Cook said the clinical practice of GH testing in adults
in the United States is inconsistent, which he attributed to several factors,
including “the high cost of GH therapy, the need for daily injections, the
lack of awareness regarding its indications, diagnosis and long-term
surveillance, and concerns about whether there are long-term risks
involved.”
Among the recommendations are the following:
- GH is not recommended for any reason other than the well-defined uses
of the drug. No data are available suggesting that GH is beneficial in
anti-aging or enhancing sport performance.
- Patients with childhood-onset GH deficiency previously treated with
GH therapy should be retested after achieving final height, and GH therapy
should be discontinued for at least one month to determine GH status before
restarting GH therapy.
- The starting dose of GH therapy for patients in transition should be
approximately 50% of the dose between the pediatric doses required for growth
and the adult dose.
- For childhood treatment of Turner’s syndrome, idiopathic short
stature and conditions other than GH deficiency, there is no indication to
retest when they achieve final height and no benefit to continuing GH therapy
in adulthood.
- The insulin tolerance test is the preferred GH stimulation test to
establish the diagnosis of adult GH deficiency in patients with childhood-onset
GH deficiency, as well as in diagnosing adult GH deficiency in general. The
arginine + GH-releasing hormone stimulation test, glucagon test and the
arginine test alone are acceptable alternatives.
The authors of the guidelines also did not recommend use
of any one commercial product due to a lack of evidence showing benefit of one
over another.
Cook and the other authors stress in the guidelines that
GH dosing should be individualized. Individuals respond differently to GH, even
after accounting for variables such as age, sex, adiposity and concurrent
medications. “Controlled trials using strict dosing regimens and measuring
clinical endpoints such as body composition and insulin sensitivity have shown
us that GH dosing should be individualized, with close attention to avoiding
side effects,” Cook said.
They also recommend that GH dosing regimens be
individualized, independent of body weight. They recommend starting with a low
dose and then gradually increasing to the minimal dose that normalizes serum
IGF-I levels without causing side effects. In patients with GH deficiency and
diabetes, obesity and previous gestational diabetes or a family history of
diabetes, the authors recommend initiating and maintaining GH therapy in low
dosages of 0.1-0.2 mg per day to avoid increasing blood glucose levels.
Finally, the authors recommend that physicians follow up
on patients at one- to two-month intervals after initiating GH therapy.
