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The effect of coenzyme Q10 in patients with congestive heart failure

M Khatta, B S Alexander, C M Krichten, M L Fisher, R Freudenberger, S W Robinson, S S Gottlieb
Annals of Internal Medicine 2000 132(8):636-640

Bibliography

PubMed
PMID 10766682
DOI
10.7326/0003-4819-132-8-200004180-00006
Funding
Supported in part by National Institute on Aging grant P60AG12583 (Claude D. Pepper Older Americans Independence Center). CoQ10 and matching placebo were supplied by Pharma Nord.
Competing interests
No specific author conflict-of-interest statement was identified in the accessible article metadata checked. Industry supplied the study product and placebo; the study also received U.S. government grant support.

Study snapshot

DesignRandomized, double-blind, placebo-controlled trial
ModelAdults with severe chronic congestive heart failure (NYHA class III–IV), LVEF <40%, and impaired peak oxygen consumption despite standard therapy; university and Veterans Affairs hospital setting.
Sample55 randomized (28 CoQ10, 27 placebo); 46 completed the 6-month trial. Nine did not complete (5 CoQ10, 4 placebo), with similar withdrawal reasons between groups.
InterventionOral CoQ10 200 mg/day versus matching placebo for 6 months, on top of standard heart-failure therapy.
Duration6 months
EndpointsPeak oxygen consumption; Exercise duration; Left ventricular ejection fraction by radionuclide ventriculography; Serum CoQ10 concentration; Mortality; Adverse events

What the study showed, in plain terms

This randomized, double-blind controlled trial tested 200 mg/day of CoQ10 for six months in 55 patients with advanced NYHA class III–IV heart failure who were already receiving standard therapy. Forty-six participants completed the study.

CoQ10 clearly increased blood CoQ10 exposure, but that biochemical change did not translate into measurable improvement in left-ventricular ejection fraction, peak oxygen consumption or exercise duration compared with placebo.

The study therefore provides useful negative evidence: in this small, severely affected heart-failure population, six months of 200 mg/day CoQ10 did not improve the objective cardiac-performance outcomes the trial was designed to test.

Key findings

Biochemical exposure: Mean serum CoQ10 rose from 0.95 ± 0.62 to 2.2 ± 1.2 μg/mL in the active-treatment group, confirming absorption and adherence at the group level.

Peak oxygen consumption: No significant treatment effect. A later evidence synthesis reports a mean change of +0.21 ± 3.4 mL/kg/min with CoQ10 versus -0.49 ± 2.4 mL/kg/min with placebo.

Exercise duration: No significant between-group improvement was demonstrated.

LVEF: No significant treatment effect by radionuclide ventriculography; later synthesis reports changes of approximately -0.3% ± 8% with CoQ10 and -0.2% ± 8.6% with placebo.

Attrition: 9/55 randomized patients did not complete the trial (5 CoQ10, 4 placebo). The published analysis therefore relied heavily on completers rather than a full modern intention-to-treat framework.

What this study can and cannot tell us

Small trial: only 55 patients were randomized and 46 completed treatment, limiting power to detect modest clinical effects or uncommon harms.

Attrition was approximately 16% overall; later systematic-review risk-of-bias assessment judged the study at high risk of attrition bias because non-completers were excluded from key analyses.

The trial focused on surrogate/objective performance outcomes rather than being powered for hospitalization or mortality.

The study predates contemporary heart-failure therapy. Product/placebo were supplied by Pharma Nord, while the study also received National Institute on Aging grant support.

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Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction Dr. Amr Yasser, PhDCardiometabolic, Musculoskeletal, Gut & Bioavailability Dr. Abdulla Mostafa, PhDCellular Senescence, Neurological, Mitochondrial & Brain-Ageing Biology