IAC: Effects of Growth Hormone Raise Caution Flag

By Michael Smith
MEXICO CITY, 04 aug 2008 -- Low doses of growth hormone reduce abdominal fat deposits in patients with HIV lipodystrophy, researchers said here. In an 18-month, placebo-controlled randomized trial, the hormone also improved blood pressure and triglyceride levels, according to Steven Grinspoon, M.D., of Massachusetts General Hospital and colleagues. On the other hand, the hormone appeared to increase some aspects of blood sugar levels, injecting "a note of caution" into the debate over using growth hormone to treat lipodystrophy, Dr. Grinspoon and colleagues said.
The study appears in the Aug. 6 issue of the Journal of the American Medical Association and was released in conjunction with the 17th International AIDS Conference.
The study is "very informative to the field," Dr. Grinspoon said, noting that off-label use of growth hormone is common.
"Even low-dose growth hormone, albeit effective in reducing cardiovascular risk factors and better tolerated than high-dose growth hormone, may increase specific glucose parameters," Dr. Grinspoon said.
The researchers enrolled 56 patients with HIV, abdominal fat accumulation, and reduced secretion of growth hormone, defined as a peak of less than 7.5 ng/mL of blood.
They were randomized to placebo or growth hormone, starting at 2 mcg/kg of body weight per day, and titrated up to a maximum of 6 mcg/kg over the 18 months of the study.
The study found that the treatment effect - the average difference between the two groups - was:
A reduction by 19 cm2 in visceral adipose tissue, which was significant at P=0.049.
A reduction of 0.8 kg in trunk fat, which was significant at P=0.04.
A drop of 7 mm Hg in diastolic blood pressure, significant at P=0.006.
A 7 mg/dL reduction in triglycerides, significant at P=0.002).
An increase in levels of insulin-like growth factor-1, a marker for growth hormone, by a treatment effect of 129 ng/mL, which was significant at P<0.001.
An increase in two-hour glucose levels (on glucose tolerance testing) of 22 mg/dL, significant at P=0.009.
Adverse events were not significantly different between the groups.
Dr. Grinspoon said that most glucose parameters were unchanged by the growth hormone, but increases on the two-hour test may be an early marker of diabetes.
He said the study showed that those whose two-hour glucose test was worsened by growth hormone were those who had poor glucose tolerance at baseline.
Because of that, he said, "I don't think growth hormone can be recommended for all people with HIV, but it might be quite useful for a subpopulation."
The study was supported by the NIH. EMD Serono provided growth hormone but made no other contribution to the study. Dr. Grinspoon reports research support on an unrelated project from EMD Serono and also serving as a consultant for the company. He also reported financial links with Theratechnologies.
Primary source: Journal of the American Medical AssociationSource reference:Lo J et al. "Low-Dose Physiological Growth Hormone in Patients With HIV and Abdominal Fat Accumulation: A Randomized Controlled Trial." JAMA. 2008;300(5):509-519.