Experts rip chelation heart study despite a hint of efficacy
A pair of federal agencies ended up splitting the cost of a $31 million study into a controversial heart therapy called chelation. But all the money bought was an ounce of efficacy and a ton of fresh controversy.
Chelation therapy, often scoffed at by mainstream physicians but heartily endorsed in the alternative medicine crowd, involves the removal of heavy metals from blood to treat heart disease. More than 100,000 people undergo the procedure every year, despite the widespread condemnation. And detractors were quick to hoot at problems with the study, which took years longer than planned, including a halt to consider a claim that the study was unethical, despite enrolling fewer patients than the trial design called for as well as a decision to lower the threshold required to achieve statistical significance.
The study created a statistical composite of death, stroke, coronary revascularization as well as hospitalization for angina among stable patients with a history of myocardial infarction and found that the chelation arm responded with a slightly lower--but statistically significant--rate of 26.5% compared to 30% in the placebo arm. Diabetics demonstrated the best response.
"The study shows chelation can be administered in a way that is safe and where there is a clear but marginal benefit," Gary Gibbons, the head of National Heart, Lung and Blood Institute, told Bloomberg. "It's an important first step, but it's just a first step. More research needs to be done before it can join the mainstream of cardiovascular care."
That's exactly the message that the Cleveland Clinic's Steve Nissen set out to debunk. A high dropout rate and the involvement of fringe doctors in the study contributed to making this study "fatally flawed," he told The New York Times. And if it persuades anyone that chelation therapy is a good approach, "it would be a public health catastrophe."
Bottom line: Chelation is as controversial as it ever was, with neither side willing to throw in the towel after looking over the data. It's likely to remain a regularly chosen alternative therapy despised by many heart specialists. And if anyone wants to resolve the dispute with data, they'll need to back new studies which are better executed than this one.