Institute of General Practice, Technische Universität München, Orleansstrasse 47, D-81667 Munich, Germany.
BMC Med. 2010 Nov 23;8:75. doi: 10.1186/1741-7015-8-75.
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.
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.
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 than trials with smaller nonspecific effects (β = -0.39, P = 0.029).
Sham acupuncture interventions are often associated with moderately large nonspecific effects which could make it difficult to detect small additional specific effects. Compared to inert placebo interventions, effects associated with sham acupuncture might be larger, which would have considerable implications for the design and interpretation of clinical trials.
虽然最近的几项大型随机试验发现针灸对无治疗或常规护理有临床相关的效果，但对针灸与假干预措施进行比较的盲法试验往往只报告了较小或没有差异。这就提出了一个问题，即（假）针灸是否与特别有效的非特异性效应有关。我们旨在研究与针灸干预相关的非特异性效应的大小。
我们检索了 MEDLINE、Embase、Cochrane 对照试验中心注册库和参考文献列表，以查找任何病症的针灸随机试验，包括假针灸和无针灸对照组。由一位审阅者提取数据，另一位审阅者验证。使用随机效应模型和倒数方差法计算汇总标准化均数差值。
共有 37 项试验（共 5754 例患者）符合纳入标准。纳入的研究在患者、干预措施、结局测量、方法学质量和报告的效应大小方面差异很大。在 32 项报告连续结局测量的试验中，假针灸与无针灸组之间的随机效应标准化均数差值为-0.45（95%置信区间，-0.57，-0.34；I2 = 54%；Egger 检验漏斗图不对称，P = 0.25）。与无针灸相比，假针灸效应较大的试验报告的针灸与假干预相比的效应较小，而与非特异性效应较小的试验相比，假针灸效应较大（β=-0.39，P=0.029）。
假针灸干预通常与中等大小的非特异性效应相关，这可能使人们难以发现较小的额外特异性效应。与惰性安慰剂干预相比，与假针灸相关的效应可能更大，这将对临床试验的设计和解释产生重大影响。
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