| Methods |
Randomised, double‐blind, placebo‐controlled cross‐over study |
| Participants |
30 adult participants with various mitochondrial disorders: 15 MELAS, 11 PEO, 1 complex I deficiency, 1 NARP, 1 ataxia‐neuropathy, 1 LHON |
| Interventions |
Coenzyme Q10 600 mg orally twice daily for 60 days and placebo for 60 days. Washout period of 67 +/‐ 8.3 days |
| Outcomes |
Outcome assessment at end of each trial period. Urine analysis of 8‐isoprostane and 8‐hydroxy‐2‐deoxyguanosine. Blood analysis of lactate, glucose, PCO2, CoQ10, bilirubin, creatine kinase and gamma‐glutamyltransferase. Questionnaires for quality of life and ADL. Maximal isometric force and near‐infrared spectroscopy on 90 s forearm ischaemic exercise test, with venous lactate, PCO2, PO2 at 1 min and 3 min post‐test. Dual‐energy X‐ray absorptometry for body composition. 15 min cycle ergometry with monitoring heart rate, inspired O2, expired CO2. VO2 and VCO2 measured at several time points. Venous lactate measured prior, and at various points during and after testing |
| Notes |
MRS of CSF lactate, N‐acetyl aspartate and choline. Serum CoQ10 was statistically significantly increased. Lactate was statistically significantly decreased at 1 min of cycle ergometry, but there was no difference at other time points. All other endpoints did not differ significantly |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Unclear risk |
Method of randomisation not specified |
| Allocation concealment (selection bias) |
Unclear risk |
Method of allocation not specified |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Incomplete outcome data adequately addressed |
| Selective reporting (reporting bias) |
Low risk |
All outcome measures in methods section were reported in results section |
| Other bias |
Unclear risk |
The inclusion of participants with mitochondrial diseases that do not have myopathy may have biased the study against a treatment effect |
| Blinding of participants and personnel (performance bias)
All outcomes |
Low risk |
This was a double‐blind trial using "identical‐appearing placebo capsules" |
| Blinding of outcome assessment (detection bias)
All outcomes |
Low risk |
Participants were randomly assigned to placebo or CoQ10 treatment |
