Honam Research Center, Medifarm Hospital, Suncheon, Republic of Korea.
Complement Ther Med. 2012 Feb-Apr;20(1-2):83-92. doi: 10.1016/j.ctim.2011.10.003. Epub 2011 Dec 7.
We investigated the relationship between the placebo effect and the trial or patient characteristics.
We identified randomized clinical trials with acupuncture, sham and no-treatment groups in which no-treatment or conventional therapy was applied to the no-treatment group. Thirty-one trials in which no treatment was applied in the no-treatment group were categorised as 'strict' trials. Thirty-nine trials in which no-treatment or conventional therapy was applied to the no-treatment group were categorised as 'less strict' trials. We calculated the treatment effect, defined as the difference in the effect size between the acupuncture and no-treatment groups, and the placebo effect, defined as the difference in the effect size between the sham and no-treatment groups. Then, a random effect meta-regression analysis was performed on the two effects with respect to trial or patient characteristics.
The treatment effect was not found to be associated with any factors in both the strict and less strict trials. However, the placebo effect was found to be associated with the publication year in both the strict and less strict trials (P=0.009 and 0.005, respectively). The placebo effect increased by 0.05 in effect size per year in trials that were published more recently.
While the treatment effect was not influenced by any trial or patient characteristics, the placebo effect was associated with the publication year.
我们研究了安慰剂效应与试验或患者特征之间的关系。
我们确定了针灸、假针和无治疗组的随机临床试验，其中无治疗组应用无治疗或常规治疗。将无治疗组应用无治疗的 31 项试验归类为“严格”试验。将无治疗或常规治疗应用于无治疗组的 39 项试验归类为“较不严格”试验。我们计算了治疗效果，定义为针灸组与无治疗组之间的效应大小差异，以及安慰剂效应，定义为假针组与无治疗组之间的效应大小差异。然后，对这两种效应与试验或患者特征进行了随机效应荟萃回归分析。
在严格和较不严格的试验中，治疗效果均与任何因素无关。然而，安慰剂效应与严格和较不严格试验中的出版年份有关（分别为 P=0.009 和 0.005）。在最近发表的试验中，安慰剂效应的效果大小每年增加 0.05。
虽然治疗效果不受任何试验或患者特征的影响，但安慰剂效应与发表年份有关。
