Institut für Biometrie, Medizinische Hochschule Hannover, Hannover, Germany.
Res Synth Methods. 2017 Dec;8(4):514-525. doi: 10.1002/jrsm.1268. Epub 2017 Oct 27.
Tο report challenges encountered during the extraction process from Cochrane reviews in mental health and Campbell reviews and to indicate their implications on the empirical performance of different methods to handle missingness.
We used a collection of meta-analyses on binary outcomes collated from a previous work on missing outcome data. To evaluate the accuracy of their extraction, we developed specific criteria pertaining to the reporting of missing outcome data in systematic reviews. Using the most popular methods to handle missing binary outcome data, we investigated the implications of the accuracy of the extracted meta-analysis on the random-effects meta-analysis results.
Of 113 meta-analyses from Cochrane reviews, 60 (53%) were judged as "unclearly" extracted (ie, no information on the outcome of completers but available information on how missing participants were handled) and 42 (37%) as "unacceptably" extracted (ie, no information on the outcome of completers as well as no information on how missing participants were handled). For the remaining meta-analyses, it was judged that data were "acceptably" extracted (ie, information on the completers' outcome was provided for all trials). Overall, "unclear" extraction overestimated the magnitude of the summary odds ratio and the between-study variance and additionally inflated the uncertainty of both meta-analytical parameters. The only eligible Campbell review was judged as "unclear."
Depending on the extent of missingness, the reporting quality of the systematic reviews can greatly affect the accuracy of the extracted meta-analyses and by extent, the empirical performance of different methods to handle missingness.
报告在心理健康领域的 Cochrane 综述和 Campbell 综述中提取数据时遇到的挑战，并指出这些挑战对处理缺失数据的不同方法的实证性能的影响。
我们使用了先前关于缺失结局数据的一项工作中汇总的一系列二分类结局的荟萃分析。为了评估其提取的准确性，我们制定了与系统评价中缺失结局数据报告相关的特定标准。使用处理缺失二分类结局数据的最流行方法，我们研究了提取荟萃分析的准确性对随机效应荟萃分析结果的影响。
在 113 项 Cochrane 综述的荟萃分析中，有 60 项（53%）被判断为“不清楚”提取（即，没有完成者结局的信息，但有关于如何处理缺失参与者的信息），42 项（37%）被判断为“不可接受”提取（即，没有完成者结局的信息，也没有关于如何处理缺失参与者的信息）。对于其余的荟萃分析，判断为“可接受”提取（即，所有试验都提供了完成者结局的信息）。总体而言，“不清楚”的提取高估了汇总优势比和研究间方差的幅度，并进一步增加了两个荟萃分析参数的不确定性。唯一符合条件的 Campbell 综述被判断为“不清楚”。
根据缺失程度的不同，系统评价的报告质量可能会极大地影响提取荟萃分析的准确性，并在一定程度上影响处理缺失数据的不同方法的实证性能。
