In chelation therapy, a biologically based practice, a drug is used to bind with and remove hypothesized excess or toxic amounts of a metal or mineral (eg, lead, copper, iron, calcium) from the bloodstream. In conventional medicine, chelation therapy is a widely accepted way to treat lead and other heavy metal poisoning (see Guidelines for Chelation Therapy).
Chelation therapy with EDTA (ethylene diamine tetraacetic acid) has also been suggested as a way to remove calcium and thus treat atherosclerosis;. However, despite > 50 yr of study, researchers have not identified any theoretical mechanism to explain how chelation therapy could treat atherosclerosis or prevent heart attacks or strokes.
Also, until recently, clinical trials showed no significant benefit from chelation therapy, and systematic reviews1 have all concluded that EDTA chelation therapy is ineffective. In 2012, a large randomized, placebo-controlled trial of alternative medicine (the Trial to Assess Chelation Therapy [TACT])2 found a barely significant benefit for chelation over placebo for aggregated outcomes (26.5% vs 30% for placebo), but not for individual outcomes (eg, death, cardiovascular events, stroke, hospitalizations). However, this study had a high drop-out rate, and there were questions about blinding and the heterogeneity of treatment centers; thus, this study did not end the controversy over chelation therapy.
Risks of chelation therapy include hypocalcemia (which is potentially serious) and delay of more effective treatment.
1Villarruz MV, Dans A, Tan F:Chelation therapy for atherosclerotic cardiovascular disease. Cochrane Database Syst Rev(4):CD002785, 2002.
2Lamas GA, Goertz C, Boineau R, et al: Effect of disodium EDTA chelation regimen on cardiovascular events in patients with previous myocardial infarction: the TACT randomized trial. JAMA. 309(12):1241–50, 2011113.