Centre for Evidence-Based Intervention, University of Oxford, Oxford, UK.
Res Synth Methods. 2017 Mar;8(1):92-108. doi: 10.1002/jrsm.1229. Epub 2017 Jan 10.
To assess the conditions under which employing an overview of systematic reviews is likely to lead to a high risk of bias.
To synthesise existing guidance concerning overview practice, a scoping review was conducted. Four electronic databases were searched with a pre-specified strategy (PROSPERO 2015:CRD42015027592) ending October 2015. Included studies needed to describe or develop overview methodology. Data were narratively synthesised to delineate areas highlighted as outstanding challenges or where methodological recommendations conflict.
Twenty-four papers met the inclusion criteria. There is emerging debate regarding overlapping systematic reviews; systematic review scope; quality of included research; updating; and synthesizing and reporting results. While three functions for overviews have been proposed-identify gaps, explore heterogeneity, summarize evidence-overviews cannot perform the first; are unlikely to achieve the second and third simultaneously; and can only perform the third under specific circumstances. Namely, when identified systematic reviews meet the following four conditions: (1) include primary trials that do not substantially overlap, (2) match overview scope, (3) are of high methodological quality, and (4) are up-to-date.
Considering the intended function of proposed overviews with the corresponding methodological conditions may improve the quality of this burgeoning publication type. Copyright © 2017 John Wiley & Sons, Ltd.
评估系统评价概述可能导致高偏倚风险的条件。
为了综合现有的概述实践指南，进行了范围综述。2015 年 10 月，使用预先指定的策略（PROSPERO 2015：CRD42015027592）对四个电子数据库进行了搜索。纳入的研究需要描述或开发概述方法。对数据进行了叙述性综合，以划定突出显示的领域，这些领域存在突出的挑战或方法学建议冲突。
有 24 篇论文符合纳入标准。对于重叠的系统评价、系统评价范围、纳入研究的质量、更新以及综合和报告结果，存在着新兴的争议。虽然已经提出了概述的三个功能——确定差距、探索异质性、总结证据——但概述无法执行第一个功能；不太可能同时实现第二个和第三个功能；并且只能在特定情况下执行第三个功能。也就是说，当确定的系统评价满足以下四个条件时：（1）纳入的主要试验没有实质性重叠，（2）与概述范围相匹配，（3）具有较高的方法学质量，（4）是最新的。
考虑到所提出的概述的预期功能以及相应的方法学条件，可以提高这种新兴出版物类型的质量。版权所有 © 2017 John Wiley & Sons, Ltd.
