INTRODUCTION Placebo response rates are relatively higher in clinical trials of disorders of brain-gut interaction. However, placebo response in functional dyspepsia (FD) has not been well described. Minimizing placebo response is important in drug development. We therefore conducted a meta-analysis to determine placebo response in trials for FD and to identify factors affecting placebo response rates. METHODS PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials were searched to identify double-blinded randomized controlled trials (RCTs) comparing medication with placebo in patients with FD. Both symptom improvement and complete relief were considered as separate primary endpoints in the analysis. Proportions of placebo patients experiencing any symptom improvement or complete relief were calculated. Dropouts after randomization for any reason were assumed to represent treatment failure for data extraction and analysis. Placebo response was pooled by a random-effects model, and effects of trial characteristics on the magnitude of placebo response were evaluated. RESULTS In 58 eligible placebo-controlled RCTs of FD from 52 selected citations, 6,732 of 17,890 participants in all trials received placebo. Pooled placebo response rates for symptom improvement and complete relief were 44.3% and 15.6%, respectively. The placebo response rate was lower when improvements were assessed for ≥8 weeks. Trials assessing complete symptom relief showed lower placebo response rates even in trials for <8 weeks. DISCUSSION Our systematic review and meta-analysis showed that pooled placebo response rates in double-blinded RCTs of FD depended on efficacy criteria. Trials assessing complete symptom relief showed stable low placebo response rates in short-term trials.

中文翻译：

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荟萃分析：功能性消化不良的安慰剂反应及其决定因素。

简介 在脑肠相互作用障碍的临床试验中，安慰剂的反应率相对较高。然而，功能性消化不良（FD）中的安慰剂反应尚未得到很好的描述。最大限度地减少安慰剂反应对于药物开发非常重要。因此，我们进行了一项荟萃分析，以确定 FD 试验中的安慰剂反应，并确定影响安慰剂反应率的因素。方法 检索 PubMed、EMBASE 和 Cochrane 对照试验中心注册库，以确定对 FD 患者进行药物与安慰剂比较的双盲随机对照试验 (RCT)。在分析中，症状改善和完全缓解都被视为单独的主要终点。计算了出现任何症状改善或完全缓解的安慰剂患者的比例。因任何原因随机化后的退出被认为代表数据提取和分析的治疗失败。通过随机效应模型汇总安慰剂反应，并评估试验特征对安慰剂反应程度的影响。结果 在 58 项符合条件的 FD 安慰剂对照随机对照试验中，来自 52 个选定的引用，所有试验的 17,890 名参与者中有 6,732 名接受了安慰剂。症状改善和完全缓解的安慰剂汇总反应率分别为 44.3% 和 15.6%。当评估改善时间≥8周时，安慰剂反应率较低。评估症状完全缓解的试验显示，即使试验时间<8 周，安慰剂反应率也较低。讨论 我们的系统回顾和荟萃分析表明，FD 双盲 RCT 中的汇总安慰剂反应率取决于疗效标准。评估症状完全缓解的试验显示，短期试验中安慰剂的反应率稳定较低。