Thursday, August 03, 2006

NCCAM chelation study site tour part II

The Trial to Assess Chelation Therapy (TACT) is a National Center for Complementary and Alternative Medicine (NCCAM) sponsored study to evaluate chelation therapy for patients with coronary artery disease. The study is conducted at multiple sites across the U.S., almost 100 of which are private clinics, with only 12 academic medical centers participating. Although this selection of study sites facilitates enrollment of large numbers of patients and has the purported advantage of simulating “real world” conditions, the approach has problems. Some authorities have expressed the view that investigation of chelation therapy should be restricted to academic centers. Supervision and credentialing of investigators at multiple non-academic sites is compromised and leaves research vulnerable to fraud, fabrication and faulty methodology, as illustrated recently by the Aventis sponsored Ketek trial.

After perusal of the TACT web site I became concerned that many of the study sites are clinics which are engaged in the practice and promotion of unscientific methods. Disclaimer: The profiles of NCCAM study sites in this and subsequent posts are not intended as criticisms of the clinics in question or their staffs. Although I disagree with the health claims to be discussed here I do not question the sincerity of the providers and respect their right to compete in the marketplace of ideas. The observations made are with the sole intention of raising questions about the quality of the research.

The first stop on our tour is Tequesta Family Practice, Tequesta Florida. Among the alternative practices featured there are heavy metal analysis for chronic fatigue, intravenous infusion of vitamins and minerals for chronic fatigue, evaluation and treatment of “dysbiosis”, evaluation of colonic “ecology” by various culturing techniques, intravenous colchicine infusion for spinal disk herniation and, of course, chelation therapy.

The clinic’s uncritical promotion of chelation raises questions about the objectivity and scientific qualification of the investigators. Chelation therapy is touted by the clinic as “one of the premier anti-aging therapies” and as useful for scleroderma, Alzheimer’s disease, rheumatoid arthritis, multiple sclerosis and porphyria.

Worse, the comments about how chelation therapy “works” reflect a misunderstanding of the pathophysiology of coronary heart disease: “… literally strip calcium out of the artery plaques that cause the clogging of the blood vessels that cause heart attacks and strokes. It can ‘soften’ the ‘hardening’ of the arteries caused by atherosclerosis, reversing the disease process.” I won’t go into a detailed explanation of the mechanisms of coronary atherosclerosis---look it up in any standard text or review---just suffice it to say that “soft” coronary plaques are much more rupture prone than “hard” plaques, and that a treatment to “soften” atherosclerotic plaques would be the wrong treatment. From the promotional comments about chelation therapy it is clear that the investigator(s) there believe that its effectiveness has already been proven.

In summary, consider these questions: Are the site investigators biased in favor of the treatment? Could such bias compromise the scientific integrity of the study, particularly given that the blinding of the investigators is faulty? Do the site investigators understand the pathophysiology of coronary heart disease and is such an understanding important for research on a treatment modality?

Part I
General criticisms of NCCAM here, here, and here.

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