How large are the nonspecific effects of acupuncture? A meta-analysis of randomized controlled trials

作者：Klaus Linde, Karin Niemann, Antonius Schneider, Karin Meißner · 发表于：BMC Medicine · 年份：2010 · DOI：10.1186/1741-7015-8-75 · 被引用次数：184 · 研究领域：Acupuncture Treatment Research Studies、Pain Management and Placebo Effect、Complementary and Alternative Medicine Studies

BACKGROUND: While several recent large randomized trials found clinically relevant effects of acupuncture over no treatment or routine care, blinded trials comparing acupuncture to sham interventions often reported only minor or no differences. This raises the question whether (sham) acupuncture is associated with particularly potent nonspecific effects. We aimed to investigate the size of nonspecific effects associated with acupuncture interventions. METHODS: MEDLINE, Embase, Cochrane Central Register of Controlled Clinical Trials and reference lists were searched up to April 2010 to identify randomized trials of acupuncture for any condition, including both sham and no acupuncture control groups. Data were extracted by one reviewer and verified by a second. Pooled standardized mean differences were calculated using a random effects model with the inverse variance method. RESULTS: Thirty-seven trials with a total of 5754 patients met the inclusion criteria. The included studies varied strongly regarding patients, interventions, outcome measures, methodological quality and effect sizes reported. Among the 32 trials reporting a continuous outcome measure, the random effects standardized mean difference between sham acupuncture and no acupuncture groups was -0.45 (95% confidence interval, -0.57, -0.34; I2 = 54%; Egger's test for funnel plot asymmetry, P = 0.25). Trials with larger effects of sham over no acupuncture reported smaller effects of acupuncture over sham intervention...