Appropriateness of sham or placebo acupuncture for randomized controlled trials of acupuncture for nonspecific low back pain: a systematic review and meta-analysis

OBJECTIVES: To establish whether sham acupuncture (SA) or placebo acupuncture (PA) is more efficacious for reducing low back pain (LBP) than other routine treatments and to discuss whether SA or PA is appropriate for randomized controlled trials of acupuncture for LBP. METHODS: Six databases were searched on 31 May 2017. We included only randomized controlled trials of adults with LBP and lower back myofascial pain syndrome. The studies had at least two control arms: a sham-controlled acupuncture arm and a routine care or waiting list arm (people who did not receive acupuncture until the end of treatment). Trials were combined using meta-analysis methods when the data allowed statistical pooling. Pooled effect sizes were calculated by random effects models. RESULTS: This review identified 7 trials (1768 participants); all were included in the meta-analysis. We found statistically significant differences in pain reduction post-intervention between SA or PA and routine care or a waiting list, with a standardized mean difference of −0.36 (95% CI −0.54 to −0.18; I(2) statistic=16%; participants=624; studies=6) for the Visual Analog Scale and −0.35 (95% CI −0.49 to −0.20; I(2) statistic=0%; participants=736; studies=1) for the Chronic Pain Grade Scale; however, no significant difference was observed between SA or PA and routine care or no treatment for post-intervention function. CONCLUSION: Compared with routine care or a waiting list, SA or PA was more efficacious for pain relief post-intervention. Concluding that SA or PA is appropriate for acupuncture research would be premature. Guidelines evaluating SA or PA control methods are needed to determine the specific effect of acupuncture over placebo.