Chelation therapy may improve cardiovascular healthBMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f2071 (Published 03 April 2013) Cite this as: BMJ 2013;346:f2071
Chelation has been used by alternative therapists to treat atherosclerosis for over half a century, with little evidence to back it. Usually given with a vitamin infusion, disodium EDTA binds divalent and trivalent cations such as calcium, magnesium, lead, zinc, and aluminum to facilitate their excretion in urine. More than 100 000 adults undergo this treatment annually in the US.
A study used a 2×2 factorial design to test 40 infusions of a 500 mL chelation solution (containing disodium EDTA, ascorbate, B vitamins, electrolytes, procaine, and heparin) against an infusion placebo, as well as an oral regimen of vitamins and minerals against oral placebo. The 1708 participants, recruited from 134 US and Canadian centres, were people over 50 years who had experienced myocardial infarction and had a serum creatinine of 2 mg/dL (1 mg/dL=88.4 µmol/L) or less.
During a median follow-up of more than four years, an effect was seen on the composite outcome of death, recurrent heart attack, stroke, coronary revascularisation, or admission to hospital for angina. This outcome was seen in 222 (26%) people randomised to chelation versus 261 (30%) of those who received placebo (hazard ratio 0.82, 95% CI 0.69 to 0.99). A similar effect was seen for the individual components of the composite outcome, although not for deaths (10% v 11% with placebo; 0.93, 0.70 to 1.25).
The authors warn that this evidence does not justify routine use of chelation, as do two linked editorials. In one (p 1291), the journal’s editors explain why they decided to publish the paper despite this 10 year, $31m (£20.5m; €24.2m) trial having been controversial since its inception. The other editorial discusses the study’s shortcomings, arguing that its results are not reliable (p 1293). Concerns include marginal statistical significance for the main finding, unbalanced dropout rates—289 (17%) of participants withdrew consent during the trial, 115 of those receiving chelation versus 174 with placebo—as well as unblinding of the sponsors and possibly researchers and participants.
Cite this as: BMJ 2013;346:f2071