“The abstract represents the first study ever to have been adequately powered to show that CoQ10 has an effect on survival in heart failure patients. These results are guideline changing, making a strong case for CoQ10, a natural substance that’s virtually without side effects, to be considered as part of the maintenance therapy for all patients with chronic heart failure,” said Svend Aage Mortensen, the first author of the study, from the Heart Centre, Copenhagen University Hospital, Denmark. “CoQ10 (also known as ubiquinone) is a vitamin like substance, which is a component of the electron transport chain participating in aerobic cellular respiration, and generates energy in the form of ATP.
Furthermore, the capacity of this oil soluble substance to exist in a completely oxidized form and a completely reduced form enables it to perform antioxidant functions. First discovered in beef heart mitochondria by Frederick Crane in 1957, the chemical structure of CoQ10 was described by Karl Folkers in 1957.
The connection with heart failure has been known for some time, with an early study by Folkers and Mortensen finding that levels of CoQ10 in cardiac biopsy samples are inversely related to the severity of heart failure (PNAS, 1985, 82 pp901-904). Reduced levels in heart failure have been explained by a ‘steal effect’, where CoQ10 is also used for its antioxidant function to address oxidative stress in the failing heart, thereby diverting supplies away from the respiratory chain. Furthermore, Mortensen added, synthesis is known to be inhibited by statins (drugs commonly prescribed to heart failure patients), which are known to reduce serum levels of CoQ10 by up to 40%.
Altogether there have been around 15 double blind studies providing CoQ10 to heart failure patients, with endpoints including ejection fractions, changes in New York Heart Association (NYHA) classification, hospitalization, symptoms, and exercise capacity. The latest meta-analysis by Domnica Fotino, from Tulane University, New Orleans, which pooled data from 13 studies involving 395 heart failure patients, found that CoQ10 increased ejection fractions by an average of 3.67% (Am J Clin Nutr 2013, 2, 268-75). “Despite the large number of studies critics have remained sceptical about the benefits of CoQ10, largely because none of these studies had been sufficiently powered to look at overall survival,” said Mortensen.
In the current study, 420 patients with NYHA Class III or IV receiving current pharmacologic therapy were randomly assigned to CoQ10 100 mg three times daily (n=202) or placebo (N=218). Patients were recruited from 17 centres in Denmark, Sweden, Austria, Slovakia, Poland, Hungary, India, Malaysia and Australia.
Results at three months showed there was a trend to reduced levels of NT-proBNP (used as a marker of the severity of heart failure) in the CoQ10group.
Result at two years show that the primary endpoint of major adverse cardiovascular event (MACE) was reached by 14% (29) of patients in the CoQ10 group versus 25% (55) of patients in the placebo group (P=0.003). Furthermore at two years, in comparison to placebo CoQ10 treated patients, had a significantly lower cardiovascular mortality (p=0.02), lower occurrence of hospitalizations (p=0.05), and showed greater improvements in functional NYHA class (p=0.047). With regard to all cause mortality at two year 9 % (18 patients) had died in the CoQ10 group compared to 17% (36 patients) in the placebo group (p=0.01). Intriguingly, fewer adverse events occurred among patients taking CoQ10 than those taking placebo (p=0.073).
CoQ10 supplements are available over the counter, with the lipid soluble form known to provide the best bioavailability. “Although CoQ10 is known to be remarkably safe, heart failure patients should consult their doctors before embarking on supplementation. To ensure no adverse interactions it would be a good idea to undertake an extra INR monitoring in patients taking anticoagulation therapy as with changes in diet or taking other new medications,” he said. Waiting for the publication of this study, this kind of dietary supplement seems to provide promising results.