Introduction: Coenzyme Q10 (CoQ10) is an antioxidant that enhances the activity of complex I and II in the Electron Transport Chain. Many preclinical and clinical studies evaluated CoQ10 for neuroprotection against Parkinson's disease (PD). The aim of this study is to synthesize evidence from published randomized controlled trials (RCTs) about the benefit of CoQ10 supplementation for patients with Parkinson's disease.
Methods: We followed the PRISMA statement guidelines during the preparation of this systematic review and metaanalysis. A computer literature search for (PubMed, EBSCO, Web of science and Ovid Midline) was carried out. We included RCTs comparing CoQ10 with placebo in terms of motor functions and quality of life. Outcomes of total Unified Parkinson's Disease Rating Scale (UPDRS), UPDRS I, UPDRS II, UPDRS III and Schwab and England scores were pooled as standardized mean difference (SMD) between two groups from baseline to the endpoint.
Results: Five RCTs (981 patients) were included in this study. The overall effect did not favor either of the two groups in terms of: total UPDRS score (SMD -0.05, 95%CI [-0.10, 0.15]), UPDRS I (SMD -0.03, 95% CI [-0.23, 0.17]), UPDRS II (SMD -0.10, 95%CI [-0.35, 0.15]), UPDRS III (SMD -0.05, 95%CI [-0.07, 0.17]) or Schwab and England score (SMD 0.08, 95%CI [-0.13, 0.29]).
Conclusion: CoQ10 supplementation does not slow functional decline nor provide any symptomatic benefit for patients with Parkinson's disease.