Amid the controversy over the new statin therapy guidelines, it was easy to overlook an equally important report from the American Heart Association's 2013 annual meeting: the finding that intravenous EDTA chelation therapy substantially reduces cardiovascular events in people with diabetes.
The report, from the NIH-funded Trial to Assess Chelation Therapy (TACT), was based on outcomes in 633 diabetic patients randomized to an EDTA-based chelation solution or a placebo. TACT showed a clear 15% reduction in absolute risk of CV events, which included a 40% reduction in total mortality, and a 40% reduction in recurrent MI.
TACT, led by Gervasio Lamas, MD, at Mount Sinai Medical Center, NY, is one of the most embattled trials in NIH history, focusing as it does on one of the most controversial of "alternative" therapies for CVD. The data, by all accounts, weighs in favor of chelation.
The diabetes findings follow a full-cohort report indicating that chelation could reduce composite CVD risk by 18%. TACT, which cost $31 million, and had multiple stops and restarts over the last decade, involved 1,708 high-risk patients.
Chelation involves intravenous infusion of ethylene diamine tetra-acetic acid (EDTA), plus ascorbic acid, magnesium chloride, potassium chloride, sodium bicarbonate, B vitamins, procainamide, and small amounts of heparin. High-risk patients typically receive as many as three 40-hour infusions
The treatment is thought to work by neutralizing and facilitating excretion of toxic heavy metals that promote oxidation, and promote formation of advanced glycation endproducts (AGEs) in the arteries and other tissues.
Overcoming Vehement Opposition
A mainstay in many "anti-aging" practices, chelation has met with vehement opposition from the mainstream cardiology community in large part because it does not fit with the lipid-based model of heart disease etiology.
Over the years, the TACT research team has been accused of scientific misconduct, poor methodology, and pseudo-science. Yet, the trial is methodologically sound, the study population is large, and the investigators involved—many at major university centers—have sterling reputations.
Commenting on the study on the MedScape website, Dr. Lamas noted that overall, the strongest benefit of chelation was in people with diabetes. The effect was much weaker in non-diabetic high-risk patients. This, he says, fits with the notion that AGEs—a known risk factor for diabetic end organ damage—play an important role in CVD.
Chelation, said Dr. Lamas, "is a very old treatment, but this is a new experiment." He added that, "the more detail you look into, the more extraordinary the effects."
In the right patient subgroups—diabetics over 50, at high-risk for CVD—chelation is a very good bet. To reduce one major CV event, one would need to treat 6.5 such patients over 5 years—a very respectable NNT statistic for any form of treatment.