Coenzyme Q10 and cardiovascular disease

Abstract

More than 5 million Americans have heart failure (HF), according to the American Heart Association. Although survival has improved with the use of drugs such as ACE inhibitors, half of patients die within 5 years of a HF diagnosis. In addition, the disease remains a frequent cause of hospitalization among Medicare beneficiaries. Coenzyme Q10 is one of the supplements most commonly used for cardiovascular diseases. Many consumers taking statins have tried this supplement to prevent or lessen muscle aches, despite conflicting findings from studies. Early studies in the 1990s also evaluated the role of coenzyme Q10 in heart failure, and initial findings were promising. ■Few data exist on the cardiovascular benefits of coenzyme Q10.■Patients with heart failure should be appropriately managed with standard therapy. ■Few data exist on the cardiovascular benefits of coenzyme Q10.■Patients with heart failure should be appropriately managed with standard therapy. In a recent meta-analysis published in January’s American Journal of Clinical Nutrition, Domnica Fotino, MD, MPH, and colleagues evaluated the effect of coenzyme Q10 on major outcomes associated with HF in randomized controlled trials. The primary outcomes were changes in left ventricular ejection fraction (EF) and New York Heart Association (NYHA) classification. Hospitalization for HF was also initially included, but this outcome was dropped because none of the reviewed studies had sufficient data on this measure. The authors identified 120 articles, with 13 eventually included in the analysis. Only randomized, placebo-controlled studies of coenzyme Q10 alone were considered. EF data were presented in 11 studies and 3 had NYHA class data. Included were 7 crossover and 6 parallel group trials; 12 were doubleblinded. The studies were completed between 1985 and 2005. Study durations ranged from 4 weeks to 28 weeks, and dosages of coenzyme Q10 varied between 60 mg to 300 mg daily. Men comprised 80% of the study populations, and the mean age varied from 50 years to 68 years. Patients’ EF ranged from 22% to 46%. Based on the meta-analysis, the researchers reported that coenzyme Q10 demonstrated a 3.67% increase in EF compared with placebo and a 0.3-point improvement in NYHA functional class; the latter finding did not achieve statistical significance. The benefit of coenzyme Q10 on EF was greater in crossover than in parallel group studies. Trials conducted before 1994, those with a duration of less than 12 weeks, those including patients with a baseline EF of 30% or greater, or those evaluating a coenzyme Q10 dosage of no more than 100 mg daily demonstrated benefit. Given the few studies in this meta- analysis, interpretation of these subgroups should be done with caution. Also, many advances in the management of heart failure have occurred since the publication of the oldest studies used in the meta-analysis. Little information is available on the drug regimens and concomitant diseases of participants. Urban Alehagan, MD, PhD, and colleagues conducted a 5-year randomized, placebo-controlled trial of 443 participants to evaluate the effect of combined selenium and coenzyme Q10 on the severity of chronic heart, all-cause mortality, and cardiovascular mortality; their findings were published online in the International Journal of Cardiology in May 2012. The daily dosages of selenium and coenzyme Q10 were 200 pg and 200 mg, respectively. The formulations had been previously documented to have good oral bioavailability. Participants were between 70 years and 88 years of age and were from a rural part of Sweden with potentially low levels of selenium. The use of standard drugs for heart failure was significantly lower than what might have been expected, and at baseline, about 50% of patients had NYHA stage 1 HF. At the end of this study, cardiovascular mortality was 5.9% for patients who received the combination treatment, compared with 12.6% among patients who received placebo. Levels of prohormone brain natriuretic peptide were significantly lower in the selenium and coenzyme Q10 group. Because withdrawal rates were high among patients with lower EF in the placebo group, the placebo and intervention groups were significantly different at the end of the study. The authors considered the study to be hypothesis-generating only, as a larger trial is needed. Coenzyme Q10 is widely promoted for its potential cardiovascular benefits, including benefits on HF. Little information exists on its benefits in patients with HF who are appropriately managed with standard therapy, including ACE inhibitors and beta-blockers.