Effect of coenzyme Q₁₀ supplementation on heart failure: a meta-analysis

Abstract

Background: Coenzyme Q₁₀ (CoQ₁₀; also called ubiquinone) is an antioxidant that has been postulated to improve functional status in congestive heart failure (CHF). Several randomized controlled trials have examined the effects of CoQ₁₀ on CHF with inconclusive results.

Objective: The objective of this meta-analysis was to evaluate the impact of CoQ₁₀ supplementation on the ejection fraction (EF) and New York Heart Association (NYHA) functional classification in patients with CHF.

Design: A systematic review of the literature was conducted by using databases including MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and manual examination of references from selected studies. Studies included were randomized controlled trials of CoQ₁₀ supplementation that reported the EF or NYHA functional class as a primary outcome. Information on participant characteristics, trial design and duration, treatment, dose, control, EF, and NYHA classification were extracted by using a standardized protocol.

Results: Supplementation with CoQ₁₀ resulted in a pooled mean net change of 3.67% (95% CI: 1.60%, 5.74%) in the EF and -0.30 (95% CI: -0.66, 0.06) in the NYHA functional class. Subgroup analyses showed significant improvement in EF for crossover trials, trials with treatment duration ≤12 wk in length, studies published before 1994, and studies with a dose ≤100 mg CoQ₁₀/d and in patients with less severe CHF. These subgroup analyses should be interpreted cautiously because of the small number of studies and patients included in each subgroup.

Conclusions: Pooled analyses of available randomized controlled trials suggest that CoQ₁₀ may improve the EF in patients with CHF. Additional well-designed studies that include more diverse populations are needed.

FIGURE 1.

Flow diagram of study-selection process. From a total of 120 potentially relevant studies, 13 randomized controlled trials that fit predefined inclusion and exclusion criteria were included in the meta-analysis. The change in ejection fraction was reported in 11 studies, and the change in NYHA functional class was reported in 3 studies. MEDLINE: http://www.ncbi.nlm.nih.gov/pubmed; EMBASE: http://www.embase.com/home; Cochrane Collaboration: http://www.thecochranelibrary.com/view/0/AboutTheCochraneLibrary.html. CHF, congestive heart failure; NYHA, New York Heart Association.

FIGURE 2.

Net percentage change in ejection fraction. The Forest plot shows the effect of CoQ₁₀ supplementation on the ejection fraction. With the use of a random-effects model, CoQ₁₀ supplementation resulted in a pooled mean net increase of 3.67% (95% CI: 1.60%, 5.74%) in the ejection fraction. The point estimate and the 95% CI for each study are denoted by filled squares and lines, respectively. The relative weight of the study is indicated by the size of the square. The open diamond indicates the point estimate for the pooled mean net change. Letters A and B were used to distinguish 2 groups reported separately within one publication. CoQ₁₀, coenzyme Q₁₀.

FIGURE 3.

Net change in NYHA classification. With the use of a random-effects model, CoQ₁₀ supplementation resulted in a pooled mean net decrease of −0.30 (95% CI: −0.66, 0.06) for the NYHA functional class, although this change was not significant. The point estimate and the 95% CI for each study are denoted by filled squares and lines, respectively. The relative weight of the study is indicated by the size of the square. The open diamond indicates the point estimate for the pooled mean net change. Letters A and B were used to distinguish 2 groups reported separately within one publication. CoQ₁₀, coenzyme Q₁₀; NYHA, New York Heart Association.