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Archive for November, 2012

The result of the Trial to Assess Chelation Therapy (TACT): As underwhelming as expected

Chelation therapy.

It’s one of the most common quackeries out there, used by a wide variety of practitioners for a wide variety of ailments blamed on “heavy metal toxicity.” Chelation therapy, which involves using chemicals that can bind to the metal ions and allow them to be excreted by the kidneys, is actually standard therapy for certain types of acute heavy metal poisoning, such as iron overload due to transfusion, aluminum overload due to hemodialysis, copper toxicity due to Wilson’s disease, acute heavy metal toxicity, and a handful of other indications.

My personal interest in chelation therapy developed out of its use by unscrupulous practitioners who blamed autism on the mercury-containing thimerosal preservative that used to be in many childhood vaccines until 2001 but has since all but disappeared from such vaccines except for one vaccine (the flu vaccine, for which a thimerosal-free alternative is available) and in trace amounts in some other vaccines. Mercury became a convenient bogeyman to add to the list of “toxins” antivaccinationists hype in vaccines. In fact, my very first post after I introduced myself on this very blog discussed the idea that mercury in vaccines was a significant cause of autism and autism spectrum disorders, and I’ve periodically written about such things ever since, in particular the bad science of Mark and David Geier, whose idea that chemical castration of children with Lupron “works” against “mercury-induced” autism is based on a chemically ridiculous idea that somehow testosterone binds mercury and makes it harder to chelate. Unfortunately, this particular autism quackery has real consequences and has been responsible for the death of a child.

Chelation isn’t just for autism, however. Despite many practitioners advertising it for autism, cancer (often with dubious studies that I might have to take a look at), Alzheimer’s disease (which Hugh Fudenberg has blamed on the flu vaccine, a claim parroted by Bill Maher, of course!), and just about every ailment under the sun, it’s easy to forget that the original use for chelation therapy promoted by “alternative medicine” practitioners was for cardiovascular disease. When it is used for coronary artery disease or autism, on a strictly stoichiometric and pharmacological basis, it is extremely implausible. Moreover, it is not without potential complications, including renal damage and cardiac arrhythmias due to sudden drops in calcium levels. Such arrhythmias can and have led to death in children, and in adults complications such as renal failure and death.
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Posted in: Clinical Trials

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The Trial to Assess Chelation Therapy: Equivocal as Predicted

The ill-advised, NIH-sponsored Trial to Assess Chelation Therapy (TACT) is finally over. 839 human subjects were randomized to receive Na2EDTA infusions; 869 were randomized to receive placebo infusions. The results were announced at this weekend’s American Heart Association meeting in Los Angeles. In summary, the TACT authors report a slight advantage for chelation over placebo in the “primary composite endpoint,” a combination of five separate outcomes: death, myocardial infarction, stroke, coronary revascularization, and hospitalization for angina:

 

Although that result may seem intriguing, it becomes less so when the data are examined more carefully. First, it barely achieved the pre-ordained level of statistical significance, which was P=.036. Second, none of the individual components of the composite endpoint achieved statistical significance, and most of the absolute difference was in coronary revascularization–which is puzzling:

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Posted in: Clinical Trials, Health Fraud, Medical Ethics, Politics and Regulation, Science and Medicine

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The Light Fantastical

What would you do if your swimming pool was dirty?  Clean it of course.  But how?  Would you take out a few pails of water, treat the water in the buckets, then toss the water back into the pool and declare the pool clean?  And if it were the bathroom that needed cleaning, would you clean it by treating a few bucket fulls of water from the pool?  Seems an odd approach to me, but, metaphorically speaking, it is the approach used by ultraviolet (UV) and laser treatment of blood.

A weird bit medical therapy, I get the occasional ‘Hey Dr. Smartypants, what do you think of this treatment?’ email. UV blood irradiation is an odd treatment, with an peculiar history.

UV light does have many effects on tissues, as a trip to Hawaii can rapidly demonstrate to a pasty Oregonian. In my world UV is used to sterilize the environment and UV kills off everything from MRSA to C. difficile to tuberculosis.  We vent potentially microbially contaminated air to the outside in part to dilute any infection but more importantly  we know that most pathogens will die when exposed to solar UV light. Do not use UV light on people as a rule, since it causes tissue damage and we fret about injury to eyes and skin.

Back in the 1930’s a physician named Knott had two patients, one with a brain abscess and one with sepsis, who he evidently cured by irradiating the patients’ blood and returning it to them.*  His rationale was since cutaneous TB can be cured by UV light (the discovery resulted in the 1903 Nobel Prize in medicine and physiology), perhaps other infections would be amenable to the therapy as well (1). (more…)

Posted in: Science and Medicine

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CAM and Creationism: Separated at Birth?

Over the past weekend, I had the opportunity to attend CSICon in Nashville, Tennessee. The Committee for Skeptical Inquiry (“CSI”) combats all sorts of pseudoscience, including creationism/creation science/intelligent design and alternative/complementary/integrative medicine. Our own Team SBM was ably represented by Harriet Hall, David Gorski and Kimball Atwood, whose presentation highlighted the credulous acceptance of CAM in some medical schools, and by Steve Novella, who gave a talk on the placebo effect and its exploitation by CAM proponents. Among many other presentations were those on the Mayan calendar and the end of the world, unmasking of (supposedly) paranormal events, and the neurobiology of memory. Pseudoscience was given a well-deserved thrashing by rational minds.

On Saturday, I once again had the pleasure of hearing Eugenie Scott ,Ph.D., the virtually one-woman anti-creationism campaign who founded and heads the National Center for Science Education (NCSE). As I listened to her talk I couldn’t help but being struck by a number of similarities in the weaknesses apparent in arguments for creationism/ creation science/intelligent design (or “ID”)and those for alternative/complementary/integrative medicine (or “CAM”). I doubt the two groups like to think of themselves as ideological twins, but gosh, they sure do look alike.

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Posted in: Evolution, History, Religion, Science and Medicine

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