The facts and fictions of chelation therapy
Chelation therapy reduced the risk of adverse outcomes in patients with a history of MI (blue).
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Chelation therapy, a type of intravenous (IV) treatment promoted by some members of the complementary and alternative medicine community, has long been mired in controversy.
Often dismissed as quackery, chelation therapy was the subject of a recently completed NIH study (Trial to Assess Chelation Therapy [TACT]) that showed the practice to be of moderate benefit to heart-attack survivors. Yet the controversy continues unabated, with some calling the study misguided or flawed and few in the conventional medical community willing to embrace chelation therapy as a legitimate option for heart patients.
How chelation therapy works
Chelation therapy consists of a series of IV administrations of disodium or calcium ethylenediaminetetraacetic acid (EDTA) mixed with minerals and vitamins.
Typically, patients recline in a chair in the clinician's office for one to four hours once to three times weekly for a series of 20 to 80 chelations. "Booster" chelations may be administered on a monthly basis or intermittently for years.
The purported benefits of chelation therapy vary but typically include the following:
- Improves such circulatory disorders as coronary artery disease (CAD), cerebrovascular disease, or peripheral vascular disease;
- Detoxifies the body of such heavy metals as lead, cadmium, and mercury; and
- Combats degenerative diseases and slows the aging process.
The procedure is usually not covered by Medicare or private insurance. The out-of-pocket costs are borne by patients and may total thousands of dollars for a single course of treatment.
The term chelation (derived from the Greek chelos or claw) refers to the mineral- or metal-binding properties of certain compounds that can hold a central cation in a pincerlike grip. Developed in Germany in 1935, EDTA was originally used as a means of binding and extracting calcium in the dye industry.
In the 1940s, Martin Rubin, Professor Emeritus of Biochemistry at Georgetown University Medical Center in Washington, D.C., discovered EDTA's effects on calcium in biological systems. This discovery led to the product's use as an anticoagulant and is still used in "purple top" blood-collection tubes. Professor Rubin's research led him to advance the use of EDTA for treatment of hypercalcemia and, eventually, lead poisoning.
In the 1950s and 1960s, several clinicians began to observe that patients treated for lead poisoning with IV EDTA experienced improvements in their cardiovascular conditions. This observation led to the widespread, but mostly empirical, use of EDTA therapy for heart patients within a growing community of alternative medicine practitioners.
Studies were undertaken, but these were mostly observational or uncontrolled and involved only small numbers of patients. Chelation therapy for other than the approved indications of refractory hypercalcemia or severe lead toxicity remained highly touted but poorly substantiated.
Clinicians practicing chelation therapy were sometimes targeted by medical boards for disciplinary action, irrespective of whether specific patient harm had occurred. Some states adopted regulations prohibiting the practice of chelation therapy. To this day, disodium EDTA is not approved by the FDA to treat any diseases. However, disodium EDTA is produced by compounding pharmacies for individual patients, so the treatment can still be obtained.
In 1998, the U.S. Federal Trade Commission (FTC) targeted the American College for Advancement of Medicine (ACAM), an organization that has trained and certified physicians in methods of safe administration of chelation therapy since the 1970s, for allegedly outsized advertising claims made regarding the treatment of atherosclerosis.
The FTC concluded that there was a lack of scientific studies to support these claims and that pro-chelation statements made by ACAM were false. As an alternative to litigation, ACAM stipulated that it would curtail public pronouncements presenting chelation therapy as an effective treatment for heart disease.
The public's enthusiasm for chelation therapy remained undiminished, however. Between 2002 and 2007, use of chelation therapy to treat heart disease and other conditions grew in the United States by nearly 68% to 111,000 people.1 As of the start of the TACT Study in 2001, it was estimated that patients received 800,000 individual EDTA infusions per year.2
Until the TACT study, mainstream clinicians widely believed that EDTA chelation therapy for conditions other than acute lead intoxication was an unwarranted and dangerous modality. This is true to the extent that excessive doses of EDTA can be nephrotoxic; cases of renal failure resulting in dialysis or death have been recorded. Additionally, transient hypocalcemia provoked by EDTA calcium sequestration can trigger cardiac arrhythmias or sudden death.
But these outcomes have generally occurred only in rare instances where EDTA is administered in too high a dose and/or too rapidly or without regard to a patient's glomerular flow rate. In 1989, a "Protocol for the Safe and Effective Administration of EDTA" was developed and subsequently updated.3
The detailed protocol provides strict criteria for patient selection and cautions clinicians to perform an initial evaluation of renal function using the Cockcroft-Gault equation and to frequently monitor renal function throughout a series of chelation treatments. Emergency procedures are outlined should adverse reactions occur.
When TACT began in 2002, Stephen Straus, MD, Director of the National Center for Complementary and Alternative Medicine (NCCAM), opined, "The public health imperative to undertake a definitive study of chelation therapy is clear. The widespread use of chelation therapy in lieu of established therapies, the lack of adequate prior research to verify its safety and effectiveness, and the overall impact of CAD convinced NIH that the time is right to launch this rigorous study."4
TACT was the brainchild of Gervasio Lamas, MD, a Miami cardiologist and experienced NIH trialist since 1995. In 1999, a patient asked Dr. Lamas about undertaking chelation with a local alternative medicine practitioner. Dr. Lamas initially discouraged the patient but later realized there was no clinical trial information upon which to base his opinion, and TACT was soon born.
Practitioners of chelation therapy were delighted at the prospect of a large study underwritten by the U.S. government, but the community was not without reservations. Some seasoned chelation practitioners, harried by years of perceived persecution by the medical establishment, were wary of a trap and did not trust Dr. Lamas.
Others questioned whether it was wise to cooperate with Dr. Lamas in view of the fact that, with or without a big study, chelation was performed anyway, albeit with the disapproval of mainstream medicine. Why risk a negative outcome?
There was even concern that, should the trial be successful, the therapy might be co-opted by conventional cardiologists or adopted by Medicare and private insurers with strict caps on reimbursement.
Many raised concerns over the possibility that the study might not be robust enough statistically. Even with a hefty $31.6 million allocation from the NIH, could enough patients of the right type be recruited and treated adequately to capture and highlight—under artificial experimental conditions—the benefits of chelation therapy?
There were also methodological concerns over what endpoints would be measured. Would the study track such hard statistics as coronary deaths or cardiac events, or would more subtle markers based on changes in circulation (e.g. angiography, radionuclide stress tests, positron emission tomography scans, coronary artery calcium scoring) be needed to delineate subtle effects of chelation?