Annals of Internal Medicine is published by the American College of Physicians on the first and third Tuesday of every month. These highlights are not intended to substitute for articles as sources of information. For a copy of an article, call 1-800-523-1546, ext. 2656, or 215-351-2656, or visit www.annals.org. Past highlights are accessible as well.
Philadelphia, May 4, 2010 – A study released today in Annals of Internal Medicine, the flagship journal of the American College of Physicians (ACP), finds that human growth hormone (HGH) improves sprint capacity in healthy recreational athletes. This is the first trial to demonstrate that HGH improves athletic performance.
During the eight-week study, 96 recreationally-trained athletes ages 18 to 40 (63 men and 33 women) were randomly assigned to receive either an inactive placebo or HGH injections. At the same time, half of the male participants were also randomly assigned to receive an additional injection of placebo or testosterone. Participants, investigators, and those who measured outcomes and analyzed data were blinded to interventions.
At eight weeks, the researchers found that HGH injections increased the athletes’ ability to sprint on a bicycle but had no effects on fitness or their ability to pull a weight or jump. The effect on sprint capacity was nearly doubled in men who also received testosterone injections.
“We found the enhancement in sprint capacity would correlate to a 0.4 second improvement over 10 seconds in a 100-meter dash.” said Dr. Ken Ho, Head of the Department of Endocrinology at St. Vincent’s Hospital in Sydney, and lead author of the study. “This improvement could turn the last place finisher in the Olympic finals into a gold medal winner.”
In addition to improvements in sprint capacity, researchers found that HGH significantly reduced fat mass among the athletes, but did not increase muscle mass. Sprint capacity returned to normal six weeks after participants stopped receiving injections. Athletes who received HGH complained of swelling and joint pain more than those who received placebo.
“In our study, we used doses of growth hormone on the low end of what is believed to be abuse in sports,” said Dr. Ho. “And for that reason, we think that the real effects of growth hormone could be far greater than what’s reported in our study. Equally, the side effects could be much more serious, as well.”
Herpes zoster, or shingles, is a condition in which painful blisters develop in the skin along the path of a nerve. Anyone who has had varicella virus infection (chicken pox) is at risk for developing shingles, but it is most common in people 60 and older. Up to 20 percent of people with shingles develop severe pain in the affected area that can last for years. This pain is known as postherpetic neuralgia, and it is more common in older populations. The herpes zoster vaccine helps prevent shingles and postherpetic neuralgia in older adults. While the vaccine has proven effective, its safety and tolerability have been questioned. Researchers studied 38,546 adults 60 years and older who had a history of chicken pox but not shingles. Participants were randomly assigned either vaccine or placebo. Researchers followed the patients for three years and asked them to report serious adverse events over the time period. About 300 participants were also asked to complete a more detailed report of any and all adverse events that occurred during the first 42 days after inoculation. Only 1.4 percent of both the vaccine and placebo recipients reported serious adverse events. More vaccine recipients (48 percent) reported vaccine-site side effects, such as redness, swelling, and tenderness.
The herpes zoster vaccine is safe, tolerable, and effective at preventing shingles. However, fewer than 10 percent of the people who are eligible for the vaccine actually receive it. At a price of about $200, it is one of the most expensive adult vaccines available. The vaccine is covered under the system Medicare uses to pay pharmacists (Part D) instead of the system it uses to pay physicians (Part B). Researchers sought to assess current knowledge, vaccination practices, and barriers to vaccination among general internists and family medicine physicians. The authors conducted a national mail and internet-based survey of 301 general internists and 297 family medicine physicians. Of the 72 percent that responded to the survey, 93 percent reported that they make the vaccine available to their patients – 49 percent by stocking the vaccine in-office and giving it there; 36 percent by asking the patient to purchase the vaccine in a pharmacy and then visit the office for vaccine administration; and 33 percent by referring patients to a pharmacy for vaccine administration. Twelve percent of respondents had stopped offering the vaccine after initially doing so. Doctors identified financial reasons for infrequent use of the vaccine. The researchers conclude that changes in reimbursement may result in more eligible people getting the vaccine.
Erythropoiesis-stimulating Agents (ESAs) have been used to achieve higher hemoglobin levels in patients with chronic kidney disease and anemia. However, clinical trials have shown that using ESA therapy to achieve higher rather than lower hemoglobin concentration is associated with an increased risk for hypertension, vascular thrombosis, and death. Researchers reviewed published results of 27 trials (10,452 patients) to summarize the effects of ESA therapy on clinical outcomes in patients with anemia and chronic kidney disease. They found that the quality of life improvements achieved through increasing hemoglobin concentration were outweighed by the significant risk for harm or death. The researchers conclude that this evidence should be incorporated in guidelines that will affect clinical practice. They suggest that the nephrology community focus on exploring the existing data and designing, conducting, and securing funding for fixed ESA dose trials.