Summary of findings 1. Coenzyme Q10 compared to placebo or conventional therapy for heart failure.
| Coenzyme Q10 compared to placebo or conventional therapy for heart failure | ||||||
| Patient or population: people with heart failure Setting: outpatient departments Intervention: coenzyme Q10 Comparison: placebo or conventional therapy | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Risk with placebo or conventional therapy | Risk with coenzyme Q10 | |||||
| All‐cause mortality follow‐up: 26 months | Study population | RR 0.58 (0.35 to 0.95) | 420 (1 RCT) | ⊕⊕⊕⊝ Moderatea | Coenzyme Q10 probably reduces all‐cause mortality | |
| 179 per 1000 | 104 per 1000 (63 to 170) | |||||
| Myocardial infarction follow‐up: 26 months | Study population | RR 1.62 (0.27 to 9.59) | 420 (1 RCT) | ⊕⊕⊝⊝ Lowa,b | The results for the effect of coenzyme Q10 on risk of myocardial infarction are inconclusive. | |
| 9 per 1000 | 15 per 1000 (2 to 88) | |||||
| Stroke follow‐up: 26 months | Study population | RR 0.18 (0.02 to 1.48) | 420 (1 RCT) | ⊕⊕⊝⊝ Lowa,b | The results for the effect of coenzyme Q10 on risk of stroke are inconclusive. | |
| 28 per 1000 | 5 per 1000 (1 to 41) | |||||
| Hospitalisation for heart failure follow‐up: mean 19 months | Study population | RR 0.62 (0.49 to 0.78) | 1061 (2 RCTs) | ⊕⊕⊕⊝ Moderatec | Coenzyme Q10 probably reduces hospitalisation for heart failure. | |
| 276 per 1000 | 171 per 1000 (135 to 215) | |||||
| Left ventricular ejection fraction (%) follow‐up: mean 8 months | MD 1.77 higher (0.09 higher to 3.44 higher) | ‐ | 650 (7 RCTs) | ⊕⊝⊝⊝ Very lowd,e | The evidence is very uncertain about the effect of coenzyme Q10 on left ventricular ejection fraction (%). | |
| Exercise capacity (assessed with treadmill exercise test (duration in seconds)) follow‐up: mean 4 months | MD 48.23 higher (24.75 lower to 121.2 higher) | ‐ | 91 (3 RCTs) | ⊕⊝⊝⊝ Very lowf,g | The evidence is very uncertain about the effect of coenzyme Q10 on exercise capacity. | |
| Adverse events follow‐up: mean 16 months | Study population | RR 0.70 (0.45 to 1.10) | 568 (2 RCTs) | ⊕⊕⊝⊝ Lowb,h | The results for adverse events associated with coenzyme Q10 are inconclusive. | |
| 158 per 1000 | 111 per 1000 (71 to 174) | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; MD: mean difference; RCT: randomised controlled trial; RR: risk ratio | ||||||
| GRADE Working Group grades of evidence High certainty. We are very confident that the true effect lies close to that of the estimate of the effect Moderate certainty. We are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low certainty. Our confidence in the effect estimate is limited; the true effect may be substantially different from the estimate of the effect Very low certainty. We have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect | ||||||
aDowngraded by one level due to indirectness. The findings are applicable only to the characteristics of participants and dosing regimen as included in this one study. bDowngraded by one level due to imprecision. The effect size has a very wide confidence interval that includes the possibilities of substantial harm, no difference, and a lower risk with coenzyme Q10. cDowngraded by one level due to risk of bias. The included study that contributed most weight to the analysis had unclear risk for selection, detection, and reporting biases, and high risk for attrition bias. dDowngraded by one level due to imprecision. The effect size has a very wide confidence interval that includes the possibility of only a minimal benefit with coenzyme Q10. eDowngraded by two levels due to substantial risk of bias. Within the 7 included studies, selection bias was unclear in 6, performance bias was high in 1, detection bias was unclear in 3 and high in 1, attrition bias was high in 4, reporting bias was unclear in 3 and high in 1, and other bias was high in 1. fDowngraded by two levels for imprecision. The effect size has a very wide confidence interval that includes the possibility of substantial harm, no difference, and a lower risk with coenzyme Q10. Also, the sample size is small. gDowngraded by one level due to risk of bias. The 3 included studies had unclear risk of selection and detection biases, and high risk of attrition bias. Two of them also had unclear risk of reporting bias. hDowngraded by one level due to indirectness. The findings are applicable only to the characteristics of participants and dosing regimen as included in the study that contributed the most weight to this analysis.