A heart disease study presented Sunday is being called a $32 million
waste of time - and even a danger to public health - by some of the
country's leading health experts.
The taxpayer-funded study
tested whether a controversial alternative therapy, called chelation,
could reduce heart attacks and other cardiovascular problems in people
who had already survived a heart attack.
Chelation therapy, which
can remove metals from the blood, is a risky procedure approved to
treat rare, life-threatening cases of heavy metal poisoning. Tens of
thousands of patients a year undergo the procedure "off-label," however,
paying around $5,000 out-of-pocket, based on the claims of doctors who
say it can cure everything from Alzheimer's to autism.
National Institutes of Health officials say they launched the study
because there has never been any evidence that the practice is effective
In a presentation Sunday, doctors said the trial found a
small overall benefit to chelation, mainly because it prevented heart
problems in people with diabetes.
Elliott Antman, chair of the
American Heart Association's Scientific Sessions program committee,
praised NIH for doing the study.
"Kudos for funding a trial that
says, 'OK, if people are lining up to have this done, let's let it
undergo rigorous clinical trials,'" Antman said in an interview before
the results were unveiled.
In a statement after the study was
presented, Antman, a cardiologist at Boston's Brigham and Women's
Hospital and professor of medicine at Harvard Medical School, added,
"Intriguing as the results are, they are unexpected and should not be
interpreted as an indication to adopt chelation therapy into clinical
Yet some doctors say the study was far from rigorously
performed, and so badly run that its marginally positive results are
Cardiologist Steven Nissen of the Cleveland Clinic,
one of the USA's most respected heart experts, says he's concerned the
study will encourage more patients to get off-label chelation instead of
taking proven medications or making lifestyle changes that clearly have
been shown to reduce heart disease.
"This study has the
potential to be extremely dangerous," Nissen says. Chelation "should not
be administered to any patients for the indication of heart disease.
... There are a lot of people, including me, who believe this was a poor
use of taxpayer dollars."
At least 30 patients have died from
off-label chelation therapy since the 1970s, including an autistic
5-year-old Pennsylvania boy, according to a 2008 report in The Medscape Journal of Medicine.
Even the study's lead author says the research should not be used to
recommend chelation therapy, and he acknowledges that its findings could
have been due to chance.
"A definitive answer on chelation
therapy will take much additional research," Gervasio Lamas, chief of
the Columbia University division of cardiology at Mount Sinai Medical
Center in Miami Beach, Fla., said in a statement. "The most exciting
part of this study is that there may be an unexpected signal of benefit.
We need to understand whether the signal is true, or whether it
occurred by chance."
The trial, known as the Trial to Assess
Chelation Therapy, or TACT, has been dogged by accusations of safety and
ethical problems from its beginnings 10 years ago.
The study was
temporarily halted in 2008 because of concerns over ethics and patient
safety. An investigation by the federal Office for Human Research
Subject Protections, which is charged with protecting patients, found
that patients may not have been properly informed of chelation's risks.
In response to such concerns, researchers revised their consent forms -
the documents that explain a study's risks and benefits to patients -
which had failed to mention the risk of death in chelation therapy.
Federal officials also ordered researchers to notify patients that the
drug they were receiving had never been approved for lead poisoning, as
implied in the consent form, and that the Food and Drug Administration
had taken the study drug off of its list of approved medications.
Stephen Kopecky, a Mayo Clinic cardiologist who participated in the
trial, says he's also concerned about the reliability of its findings.
The overall benefits were very small, with 26.5% of those randomly
assigned to chelation experiencing a cardiovascular problem, compared
with 30% of those randomly assigned to a placebo infusion. Even more
concerning, that benefit passed the bar for statistical significance -
the standard for judging whether a result is real or a fluke - by only
Further analysis showed the benefits were limited to those with diabetes, rather than for patients overall.
Under the best of circumstances, that's not a strong result, says
anesthesiologist Kimball Atwood of Newton-Wellesley Hospital in
Massachusetts, who has followed the study from its beginning.
This study's findings are even more questionable, however, Kopecky says,
because patients who got chelation had lower bad cholesterol levels
than the placebo group at the start of the trial. That could explain
most of their reduced risk for a second heart attack, says Kopecky,
president of the American Society for Preventive Cardiology.
addition, 30% of patients stopped getting their assigned treatments, and
17% withdrew their consent, preventing doctors from including their
data or even contacting them to see if they were still alive, Kopecky
That large of a dropout rate - which is normally no more than about 3% - could skew the study's findings, Kopecky says.
"That's a big concern any time a study shows a benefit on something that's not highly regulated by the FDA," Kopecky says.
Kopecky also acknowledges that there's no known biological basis for
why removing metals from the blood would help heart disease. "That is a
million-dollar question," he said.
More than half the trial sites
were led by doctors who practice chelation, says Paul Armstrong, a
professor of cardiology at the University of Alberta, chosen to discuss
the study on a panel at the heart meeting. That could lead to a bias in
favor of chelation, Atwood says.
"All of these factors call into
question the results," says Michael Carome, deputy director of the
advocacy group Public Citizen's Health Research Group.
officials say the trial was worthwhile. Gary Gibbons, director of the
National Heart, Lung, and Blood Institute, says the study was a
"breakthrough" not for proving that chelation works, but for
"establishing that this chelation therapy regimen can be administered in
a safe manner in the context of a clinical trial."