Growth Hormone May Benefit Lungs in cystic fibrosis

In patients with cystic fibrosis, recombinant human growth hormone not only has beneficial effects on weight and height but also on many pulmonary measures, researchers reported.

There is also some evidence that the treatment may improve bone mineral content and reduce the need for in-patient care, according to Michael White, PharmD, and colleagues at the University of Connecticut/Hartford Hospital Evidence-Based Practice Center in Hartford, Conn.
On the other hand, there is no evidence that the therapy prolongs life or improves health-related quality of life, White and colleagues reported online in Pediatrics.
The findings come from an evidence review sponsored by the Agency for Healthcare Research and Quality, in which White and colleagues looked at 18 reports representing findings from 10 clinical trials and eight observational studies.
"Patients with cystic fibrosis and their families have long looked for ways to manage this disease," agency director Carolyn Clancy, MD, said in a statement. "This report gives patients and their families excellent information that they can use, in consultation with their doctors, to make decisions about care."
To look for evidence, White and colleagues searched MEDLINE (starting from 1950 through April 2010) and well as the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews from the earliest possible date through April 2010.
In the controlled trials, they found that several markers of pulmonary function appeared to be significantly improved. Specifically, the weighted mean difference between patients getting the hormone and those getting a placebo or no treatment other than standard care was:

• 0.67 liters for forced vital capacity
• 9.34% for percent predicted forced vital capacity
• 0.23 liters for forced expiratory volume in one second (FEV₁)

Moreover, there were significant improvements in anthropometric measures, including positive weighted mean differences in change in height, height velocity, weight, weight velocity, body mass index, and lean body mass.
For example, those getting the hormone added weight at a velocity of 2.15 kilograms a year on average, compared with controls, the researchers found.
Also, the weighted mean difference between treated patients and controls for bone mineral content was 192 grams, which was also significant.
The results of observational studies generally supported the findings of the clinical trials, White and colleagues found.
On the other hand, several measures, including such things as percent predicted FEV₁, FEV₁ Z-score, and exercise work rate, did not show a significant difference between those getting the hormone and controls, they found.
But despite those findings, there's not enough evidence to determine the effect of human growth hormone on intravenous antibiotic use during therapy, pulmonary exacerbations, health-related quality-of-life, bone consequences, or total mortality.
White and colleagues did find "moderate evidence" that suggests the hormone reduces the rate of in-patient care, with a weighted mean difference between the groups of minus 1.62 episodes a year.
On the other hand, the therapy significantly increased fasting blood glucose and nonsignificantly increased stimulated glucose concentrations, although long-term glucose control, as assessed by hemoglobin A1c, was not affected.
The researchers concluded that human growth hormone is "a promising therapy" for cystic fibrosis. But, they added, "there are a number of important research questions that should be answered before its role can truly be discerned."
They called for a large, multicenter, randomized, placebo-controlled trial to investigate the impact of the hormone as measured by the need for in-patient care, mortality, bone fractures, and health-related quality of life.