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7Nov 2012

$30 million chelation study: Small benefit, or flawed research?

$30 million chelation study: Small benefit, or flawed research?

The story by Andrew Pollack at The New York Times on a new drug regimen for heart disease begins simply enough:

To the surprise of many cardiologists, a controversial alternative therapy proved beneficial to people with heart disease, reducing the rate of death and cardiovascular problems in a clinical trial, researchers said on Sunday.

But did the alternative treatment really "prove beneficial?" Not if you read Pollack's second graf, in which he snatches back what he said in the first:

The benefit of the treatment, known as chelation therapy, barely reached statistical significance, and there were questions about the reliability of the study. Even the investigators in the trial said the results were insufficient by themselves to justify recommending use of the treatment.

That makes it clear that the study didn't "prove" anything. Why would Pollack report in one graf that the treatment reduced death and cardiovascular problems, and in the next that the evidence was barely statistically significant, questionable, and insufficient to justify use of the treatment. Does it reduce death and disease, or not?

In his third graf, Pollack tacks back again, saying the finding "should provide some vindication to the National Institutes of Health for sponsoring the $30 million study." Then he quotes critics, one of whom says the study was "fatally flawed," and that "if people got the mistaken idea from the study that chelation was beneficial 'it would be a public health catastrophe.'" And yet here is the headline: "Much-Debated Treatment for Heart Disease Shows Slight Benefit in Clinical Trial."

The study dealt with an alternative treatment known as chelation therapy, which, Pollack reports, involves the use of drugs to remove metals from the bloodstream. Some skeptics, he reports, said there was not enough evidence for its effectiveness to justify a clinical trial--and yet the government spent $30 million on it.

Others were far more critical than Pollack. The bioethicist Art Caplan wrote at that the study, presented at the American Heart Association annual meeting, was a waste of $30 million, because there is no evidence that chelation works:

A doctor gives you ethylenediaminetetraacetic acid via IV.  This chemical is widely used to dissolve limescale, the chalky deposit found in kettles, hot water boilers and pipes. That is the extent to which the chemical is proven to do any good. There is no scientific reason to explain why something that can dissolve granular, sand-like deposits in your water heater should be capable of clearing out clogged vessels in a heart. 

A better strategy to prevent heart disease is to lose weight, avoid smoking, and stay fit, he writes.

Larry Husten at Cardiobrief wrote that the study "turned up the first substantial evidence in support of chelation therapy," but he noted in his lede that the finding was "likely to surprise and baffle much of the mainstream medical community." But the lede gave rise to a headline which, like Pollack's, overstates the case: "NIH Trial Gives Surprising Boost to Chelation Therapy."

Marilynn Marchione of the AP turned in a nice lede that emphasizes the criticism: "A heart disease treatment that many doctors consider to be fringe medicine unexpectedly showed some promise in a federal study clouded by ethical and scientific controversy, causing debate about the results." That reflects the ambivalence over the study as well as anything I read. Michelle Fay Cortez of Bloomberg also got the skepticism into the lede.

The key here was to write a story that acknowledged the barely positive findings while hitting the point strongly that this does not mean patients should demand the treatment from their doctors. Stories and headlines that did not emphasize the numerous problems with the study missed the mark.

-Paul Raeburn


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