Clinical Briefs
With Comments from John La Puma, MD, FACP
Coenzyme Q10 for CHF
August 2000; Volume 3; 96
Source: Khatta M, et al. The effect of coenzyme Q10 in patients with congestive heart failure. Ann Intern Med 2000;132:636-640.
"Coenzyme q10 is commonly used to treat congestive heart failure (CHF) on the basis of data from several unblinded, subjective studies. Few randomized, blinded, controlled studies have evaluated objective measures of cardiac performance.
"To determine the effect of coenzyme Q10 (CoQ10) on peak oxygen consumption, exercise duration, and ejection fraction, we conducted a randomized, double-blind, controlled trial at University and Veterans Affairs hospitals. Fifty-five CHF patients with New York Heart Association class III and IV symptoms, ejection fraction less than 40%, and peak oxygen consumption less than 17.0 ml/kg/min (or < 50% of predicted) during standard therapy were randomly assigned to 200 mg/d CoQ10 or placebo. Forty-six patients completed the study.
"We measured left ventricular ejection fraction (measured by radionuclide ventriculography) and peak oxygen consumption and exercise duration (measured by a graded exercise evaluation using the Naughton protocol) with continuous metabolic monitoring.
"We found that although the mean (± SD) serum concentration of CoQ10 increased from 0.95 ± 0.62 mg/ml to 2.2 ± 1.2 mg/ml in patients who re-ceived active treatment, ejection fraction, peak oxygen consumption, and exercise duration remained unchanged in both the CoQ10 and placebo groups.
"We conclude that CoQ10 does not affect ejection fraction, peak oxygen consumption, or exercise duration in patients with congestive heart failure receiving standard medical therapy."
COMMENT
What is CoQ10, what does it do, and why do so many people take it?
CoQ10 (or ubiquinone) is a fat-soluble, ubiquitous antioxidant, membrane stabilizer, and mitochondrial component. It is part of ATP production, and is an essential cofactor in many enzymatic reactions. The proposed mechanism of action is based on a relative deficiency of CoQ10 in CHF patients. I could find no published studies which show that specifically reversing the level of documented deficiency improves the clinical course of CHF.
CoQ10 supplements are approved in Japan for treatment of CHF. They may interact with statins and some oral hypoglycemics (they both reduce CoQ10 levels), vitamin E (its antioxidant level is prolonged), and warfarin (it has a reduced effect). CoQ10 supplements are also used for gum disease, chronic fatigue syndrome, chemotherapeutic support, and anginal relief.
But do they work? Other controlled studies, reported here previously (see Alternative Medicine Alert, March 1998, pp. 25-27), have demonstrated significant improvements in dyspnea, peripheral edema, and insomnia among CoQ10 groups, as compared with control.
The verdict is not in, but these well-gathered and carefully controlled data suggest that if they do work in patients with advanced failure, it’s not because of an improved ejection fraction or improved exercise tolerance. It may be because of a perception of improved quality of life—even in this negative study, CoQ10 patients reported an improved quality of life over placebo patients.
Symptoms count for a lot in this disease, which so many people find limiting. It may be that we simply do not know how to measure the effects of CoQ10, and patients do. As is the case with many supplements, a strong dose of placebo may be improving our patients’ shortness of breath, swelling, and sleeping. Whatever the mechanism, no harm, no foul.
Recommendation
These data are not enough to warn patients off CoQ10, but conventional therapy with ACE inhibitors, diuretics, digoxin, and beta-blockers remain the cornerstones of CHF therapy. Avoid CoQ10 (and most supplements) in the presence of warfarin.
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