Efficacy of electro-acupuncture and manual acupuncture versus sham acupuncture for knee osteoarthritis: statistical analysis plan for a randomized controlled trial

Background: Acupuncture therapies are widely used for knee osteoarthritis (KOA), despite contradictory evidences. Current study is designed to determine the efficacy of electro-acupuncture and manual acupuncture versus sham acupuncture for KOA. Methods/design: Current study is a multi-center, three-arm, randomized controlled trial which will enroll 480 participants with KOA in China. Participants will be randomly assigned (1:1:1) to receive 24 sessions of electro-acupuncture, manual acupuncture, or sham acupuncture over 8 weeks. The primary outcome is the response rate - the proportion of patients who simultaneously achieve minimal clinically important improvement in pain and function domains at 8 weeks. The primary outcome will be analyzed using Z-test with intention-to-treat set. Secondary outcomes contain pain, function, global patient assessment and quality of life. Full details of the statistical analysis plan for the primary and secondary outcomes will be described in this article. The statistical analysis plan was written and submitted without knowledge of the study data. Discussion: The data will be analyzed according to this pre-specified statistical analysis plan to avoid data-driven analysis and enhance the transparency of current trial. The trial will provide high-quality evidence on the efficacy of acupuncture for KOA.