This article is more than 5 years old. Information may no longer be current.
EDTA chelation therapy failed to improve QOL in patients with stable CAD
The use of IV ethylenediaminetetraacetic acid, or EDTA, chelation therapy does not have a measurable effect on quality of life for patients with stable, mainly asymptomatic CAD, according to results from a recent prospective study.
Researchers assessed a subset of 911 participants in the NIH’s randomized, double blind TACT trial, a study of 1,708 patients aged at least 50 years with stable coronary disease. In the TACT study, investigators randomly assigned patients, all of whom had experienced an MI at least 6 months prior, to 40 infusions of a multicomponent EDTA chelation solution or placebo. The results of intent-to-treat analysis indicated that chelation significantly decreased incidence of the primary composite endpoint of mortality, recurrent MI, stroke, coronary revascularization or hospitalization for angina.
In the current study, the researchers assessed quality of life (QOL) in the subset population using an array of validated QOL instruments, including the Duke Activity Status Index, which measures cardiac-related functional status on a scale from 0 to 58.2, and the Medical Outcomes Study 36-Item Short-Form Mental Health Inventory-5, which assesses psychological distress on a 100-point scale. These QOL measures were evaluated at 6, 12 and 24 months after the patients were randomly assigned to EDT chelation (n=451) or placebo (n=460). The baseline clinical and QOL characteristics were comparable between the two groups.
Duke Activity Status Index improved in both groups during the first 6 months of treatment, but there was no significant difference in QOL according to treatment at any time point. The treated group had a mean score of 24.6 at baseline, 29.1 at 6 months, 29.4 at 12 months and 27.1 at 24 months vs. 23.5 at baseline, 27 at 6 months, 26.3 at 12 months and 25.1 at 24 months in the placebo group (mean adjusted difference between groups=0.9; P=.27). Similarly, there was no statistically significant evidence of a treatment-related difference in QOL as indicated by the Mental Health Inventory-5 (mean adjusted difference=1; P=.08).
None of the evaluated secondary QOL measures reflected a treatment-related difference at any evaluated interval. Subgroup analysis also indicated no differences in treatment impact on QOL according to diabetes status, anterior MI or the presence of HF symptoms at baseline, among other factors.
The researchers cited two possible explanations for their findings — EDTA chelation alters aspects of CAD progression that lack symptomatic correlates, or the TACT trial included a population that was not likely to exhibit a QOL improvement due to a low level of cardiac symptoms at enrollment.
“Our study shows that in a population of stable, largely asymptomatic CAD patients with prior MI, use of EDTA chelation therapy did not produce a measurable change in health-related QOL during 2 years of follow-up,” they concluded.
Disclosure: See the full study for a list of relevant financial disclosures.