Chelation therapy, an unproven alternative medicine in the treatment for heart disease, modestly reduced cardiovascular events for adults aged 50 and older who had suffered a prior heart attack, according to new NIH-supported research.
Results from the chelation arm of the Trial to Assess Chelation Therapy (TACT), which will be published in the March 27 issue of the Journal of the American Medical Association, showed that infusions of a form of chelation therapy using disodium ethylene diamine tetra-acetic acid (EDTA) reduced cardiovascular events by 18 percent compared to a placebo treatment. Investigators stated that more research is needed before considering routine use of chelation therapy for all heart attack patients. The EDTA-based chelation solution also contained high doses of vitamin C, B-vitamins, and other components.
Between 2002 and 2007, use of chelation therapy to treat heart disease and other diseases grew in the United States by nearly 68 percent to 111,000 people, according to the 2008 National Health Statistics Report. Chelation therapy removes heavy metals and minerals from the blood, such as lead, iron, copper, and calcium. Disodium EDTA is not approved by the FDA to treat heart disease, the leading cause of death for both men and women in the United States.
“This study sheds light on a scientific controversy that has previously been untested,” said Gary H. Gibbons, M.D., director of the NIH's National Heart, Lung, and Blood Institute (NHLBI). “We now know more about the safety and efficacy of this therapy than we did before the study. Further research is needed to fully understand these results before this treatment can be applied to the routine clinical care of heart attack patients. We do not yet know whether this therapy can be applied to most people with heart disease, which patients may potentially benefit from it, or how it may work.”
From 2003 to 2010, TACT investigators enrolled 1,708 adults aged 50 and older at 134 sites in the United States and Canada. Study participants had suffered a heart attack six weeks or more before enrollment (average was about 4.5 years). They were assigned randomly to receive 40 infusions of either the disodium EDTA chelation solution or a placebo solution. Patients also were randomly assigned to receive high doses of oral vitamins and minerals or an identical oral placebo. Most participants also took standard medicines for heart attack survivors, such as aspirin, beta blockers, and statins. They were followed for a minimum of one year and up to five years, with follow-up ending in October 2011.
“The trial demonstrated that chelation therapy can be safely administered when rigid quality control parameters are in place, and that, under these conditions, therapy has modest benefits,” said Gervasio A. Lamas, M.D., the study’s principal investigator and chairman of Medicine and chief of the Columbia University Division of Cardiology at Mount Sinai Medical Center in Miami Beach, Fla. “Safety remained paramount throughout the course of the trial.”
The study assessed a composite primary endpoint that included death, recurrent heart attack, stroke, hospitalization for angina (chest pains sometimes indicating an impending heart attack), and coronary revascularization (coronary stenting or bypass surgery). The TACT investigators reported a clinically modest, but statistically significant, benefit of chelation therapy compared with placebo infusions. Fewer participants in the chelation group (222, or 26 percent) experienced cardiovascular events than did participants in the placebo group (261, or 30 percent). There was no statistically significant effect on mortality. The study was not designed to have enough patients to detect a difference in mortality.
Some subgroups of study participants, who were predefined at the start of the study, appeared to receive particular benefit from chelation therapy, specifically adults with diabetes, who constituted almost a third of the study population. Lamas noted that subgroup analyses cannot be considered conclusive, but can guide future research.
TACT was not designed specifically to discover how or why chelation might benefit heart attack patients, which limits the potential application of these results.
TACT was supported by grants from the NHLBI (U01HL092607) and the NIH's National Center for Complementary and Alternative Medicine (U01AT001156).
For more information or to arrange an interview with an NIH spokesperson, please contact the NHLBI Communications Office at 301-496-4236 or firstname.lastname@example.org. To schedule an interview with Dr. Lamas, contact Joanna Palmer at 305-674-2600 or Joanna.Palmer@msmc.com.
- Clinicaltrials.gov page about TACT
- NIH news release: NIH launches large clinical trial on EDTA chelation therapy for coronary artery disease
- Statement from NHLBI Director Gary H. Gibbons, M.D., on the TACT preliminary results:
- Statement from NHLBI Director Gary H. Gibbons, M.D., on the TACT vitamin component:
- TACT Questions & Answers: