Is acupuncture no more than a placebo? Extensive discussion required about possible bias (Review)

Numerous randomized controlled trials (RCTs) of acupuncture have been conducted in recent years. The results of several studies implied that acupuncture was only a powerful placebo; however, certain studies demonstrated that verum acupuncture had a greater effect than placebo and the mechanisms between a verum acupuncture group and a placebo/sham group were different. Researchers attempted to investigate the inherent factors that may potentially influence the results of trials. Certain problems observed in acupuncture RCTs also occurred in RCTs in other fields, including insufficient sample size, high dropout rates, inadequate follow-up and randomization. The study of acupuncture is so complex that specific methodological challenges are raised, which are frequently overlooked, including sham interventions, blinding, powerful placebo effects (even stronger than an inert pill) and variations in acupuncture administration. The aforementioned problems may contribute to bias, and researchers systematically attempt to solve these problems. The present review aimed to suggest techniques to design high-quality studies, minimize the placebo effect and optimize acupuncture administration in acupuncture studies. If these problems are addressed, then the results of acupuncture studies may be different.