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Am Fam Physician. 2021;104(5):458-459

Author disclosure: No relevant financial affiliations.

Clinical Question

Does coenzyme Q10 decrease mortality and hospitalizations in patients with heart failure?

Evidence-Based Answer

In patients with chronic heart failure, supplementation with coenzyme Q10 may reduce all-cause mortality (absolute risk reduction [ARR] = 7.5%; 95% CI, 0.9% to 11.6%; number needed to treat [NNT] = 13; 95% CI, 9 to 111) and heart failure–related hospitalization (ARR = 10.5%; 95% CI, 6.1% to 14.1%; NNT = 10; 95% CI, 7 to 16).1 (Strength of Recommendation [SOR]: B, based on inconsistent or limited-quality patient-oriented evidence.) Adverse effects are generally mild and may be only slightly increased with coenzyme Q10 supplementation.1 (SOR: B, based on inconsistent or limited-quality patient-oriented evidence.)

Practice Pointers

Heart failure is associated with high rates of morbidity and mortality and is classified as systolic (reduced ejection fraction) or diastolic (preserved ejection fraction).2 The prevalence of any heart failure classification in the United States in 2012 was 2.4% and is expected to be at least 3% by 2030.3 Serum oxidants are elevated in persons with heart failure, are correlated with severity of disease, and predict mortality.3 Coenzyme Q10 is a nutritional supplement with antioxidant properties. Low plasma concentrations of coenzyme Q10 have been found to be an independent predictor of mortality in patients with heart failure.4 The authors of this Cochrane review sought to assess the safety and effectiveness of coenzyme Q10 supplementation, compared with placebo or conventional therapy, in persons with heart failure.1

This Cochrane review included 11 randomized controlled trials (RCTs) and 1,573 participants (1,535 adults; 38 children).1 The follow-up time ranged from one to 26 months. Primary outcomes included all-cause mortality, risk of myocardial infarction and stroke, heart failure–related hospitalization, improvement in left ventricular ejection fraction, and adverse effects. Study participants included patients with any type of chronic heart failure regardless of severity. Acute heart failure was the only exclusion criterion. Significant variation in the dosing of coenzyme Q10 was noted in eight out of 11 included studies (range = 30 to 400 mg per day). Five studies were performed in Asia, two in Europe, one each in Russia, Australia, and the United States, and one study enrolled participants from Europe, Australia, and Asia. Data in this review regarding all-cause mortality, heart failure–related hospitalization, and adverse effects were derived primarily from the latter, a double-blind RCT.

Patients with New York Heart Association class III or IV heart failure who received coenzyme Q10 supplementation, 300 mg per day, had lower all-cause mortality after 26 months (ARR = 7.5%; 95% CI, 0.9% to 11.6%; NNT = 13; 95% CI, 9 to 111). However, this was based on a single double-blind RCT (n = 420 adults). Supplementation with coenzyme Q10 did not significantly decrease the risk of myocardial infarction or stroke.

Heart failure–related hospitalizations were reduced at 19 months in patients with New York Heart Association class III or IV heart failure who were treated with coenzyme Q10, 150 to 300 mg per day (ARR = 10.5%; 95% CI, 6.1% to 14.1%; NNT = 10; 95% CI, 7 to 16; two RCTs; n = 1,061 adults). It is unclear how duration of treatment affected outcomes.

Common adverse effects of coenzyme Q10 include mild gastrointestinal symptoms, such as nausea, vomiting, and diarrhea. Only two of the 11 studies reported on adverse effects, but neither specified symptoms. In both studies, adverse effects were reported slightly more often in the coenzyme Q10 group vs. placebo or standard therapy; however, pooled analysis did not reveal a statistically significant greater risk.

Limitations of this review include the inconsistent daily dosage of coenzyme Q10 used in the studies. Most studies did not use an intention-to-treat analysis. There is questionable generalization to a U.S. population; most conclusions in this review are based on one RCT that did not enroll U.S. participants.

In 2013, the American College of Cardiology Foundation and the American Heart Association recommended against the use of nutritional supplements (including coenzyme Q10) for the treatment of heart failure.5 The 2017 update to this practice guideline did not address coenzyme Q10. The approximate cost of a one-month supply of the 200-mg dose of coenzyme Q10 is $10.6 At this time, there is insufficient evidence to support, or refute, the use of coenzyme Q10 in patients with heart failure.

The practice recommendations in this activity are available at

Editor's Note: The ARRs, NNTs, and their corresponding CIs reported in this Cochrane for Clinicians were calculated by the author based on raw data provided in the original Cochrane review.

The opinions and assertions contained herein are the private views of the author and are not to be construed as official or as reflecting the views of the U.S. Air Force, the Department of Defense, or the Uniformed Services University of the Health Sciences.

These are summaries of reviews from the Cochrane Library.

This series is coordinated by Corey D. Fogleman, MD, assistant medical editor.

A collection of Cochrane for Clinicians published in AFP is available at

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