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New TACT Analysis Shows EDTA Chelation Therapy Has Beneficial Outcomes for People With Diabetes

November 21, 2013
Josephine P. Briggs, M.D.
Josephine P. Briggs, M.D.

National Center for Complementary and Alternative Medicine

View Dr. Briggs' biographical sketch

Earlier this week, a new secondary analysis of results of the Trial to Assess Chelation Therapy (TACT) was published in the journal Circulation: Cardiovascular Quality & Outcomes and presented at the American Heart Association meeting. The analysis suggests that the EDTA-based chelation treatments produced a marked reduction in cardiovascular events and death in participants with diabetes. Furthermore, the results suggest that treatments had no benefit in those who did not have diabetes.

TACT’s initial report published in the Journal of the American Medical Association earlier this year showed a modest, but significant, reduction in a cardiovascular events in the EDTA-treated participants. But what was particularly surprising to me, personally, was that an initial subgroup analysis showed a greater effect of EDTA treatment among participants with a self-reported history of diabetes. When these data in the 633 participants with diabetes were examined further, they showed a 41 percent overall reduction in the risk of any cardiovascular event; a 40 percent reduction in risk of cardiovascular mortality, non-fatal stroke, or non-fatal myocardial infarction; a 52 percent reduction in recurrent heart attacks; and a 43 percent reduction in death from any cause. In contrast, there was no significant benefit of EDTA treatment in in the subgroup of 1075 participants who did not have diabetes.

To me, these findings are a reminder that we need to keep an open mind in research, as scientific investigation is rich with examples of unexpected outcomes. TACT was not designed specifically to discover how or why chelation might benefit people with diabetes. The sub-group analysis of this clinical trial, although pre-specified, cannot be considered to provide a definitive answer. But it does generate intriguing hypotheses. These effects are large and potentially clinically important. This analysis suggests strongly that more research is needed to examine possible benefits of chelation in people with diabetes and the potential mechanisms.

Note: Post was updated to correct the number of study participants with diabetes (633, not 663).


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Keeping an open mind means keeping a mind open to the possibility that generated hypotheses, especially from a subgroup analysis of an ethically and methodologically problematic trials ( ), are dead ends. Is there any particular reason to believe that EDTA would reduce cardiovascular events in diabetics and not others (especially since chelationists have claimed it works for everyone)? Should we not keep our minds open to the possibility that this is just a case of torturing a data set until it gives an answer that makes the funding agency seem less misguided in its funding choices?Let’s also keep our minds open to the possibility that costs have already been sunk into TACT and that we cannot afford to sink more money into testing implausible hypotheses (instead of pursuing investigations that are more likely to be fruitful). Perhaps now is a good time to take a TACTless approach in formulating a federal research agenda. 

Very helpful post.

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