Randomized clinical trials underpin evidence‐based clinical practice, but flaws in their conduct may lead to biased estimates of intervention effects and hence invalid treatment recommendations. The main approach to the empirical study of bias is to collate a number of meta‐analyses and, within each, compare the results of trials with and without a methodological characteristic such as blinding of participants and health professionals. Estimated within‐meta‐analysis differences are combined across meta‐analyses, leading to an estimate of mean bias. Such “meta‐epidemiological” studies are published in increasing numbers and have the potential to inform trial design, assessment of risk of bias, and reporting guidelines. However, their interpretation is complicated by issues of confounding, imprecision, and applicability. We developed a guide for interpreting meta‐epidemiological studies, illustrated using MetaBLIND, a large study on the impact of blinding. Applying generally accepted principles of research methodology to meta‐epidemiology, we framed 10 questions covering the main issues to consider when interpreting results of such studies, including risk of systematic error, risk of random error, issues related to heterogeneity, and theoretical plausibility. We suggest that readers of a meta‐epidemiological study reflect comprehensively on the research question posed in the study, whether an experimental intervention was unequivocally identified for all included trials, the risk of misclassification of the trial characteristic, and the risk of confounding, i.e the adequacy of any adjustment for the likely confounders. We hope that our guide to interpretation of results of meta‐epidemiological studies is helpful for readers of such studies.

中文翻译：

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解释元流行病学研究的结果（以MetaBLIND研究为例）时要考虑的十个问题。

随机临床试验是基于证据的临床实践的基础，但是其行为上的缺陷可能会导致干预效果的估计偏差，从而导致无效的治疗建议。偏倚的经验研究的主要方法是整理许多荟萃分析，并在每项分析中比较具有和不具有方法特征（例如参与者和卫生专业人员失明）的试验结果。荟萃分析将估算的内部分析差异进行合并，从而得出均值偏差的估算值。这样的“元流行病学”研究越来越多地发表，并且有可能为试验设计，偏倚风险评估和报告指南提供信息。但是，它们的解释由于混淆，不精确和适用性问题而变得复杂。我们开发了解释元流行病学研究的指南，并使用MetaBLIND进行了说明，这是一项有关致盲影响的大型研究。将普遍接受的研究方法学原理应用于元流行病学，我们提出了10个问题，涵盖了解释此类研究结果时要考虑的主要问题，包括系统错误风险，随机错误风险，与异质性相关的问题以及理论上的合理性。我们建议，元流行病学研究的读者应全面反思研究中提出的研究问题，是否明确确定了所有纳入试验的实验干预措施，试验特征分类错误的风险以及混淆的风险，即对可能的混杂因素进行任何调整的充分性。