Nolting Alexandra, Perleth Matthias, Langer Gero, Meerpohl Joerg J, Gartlehner Gerald, Kaminski-Hartenthaler Angela, Schünemann Holger J
Abteilung Fachberatung Medizin, Gemeinsamer Bundesausschuss, Berlin, Germany.
Z Evid Fortbild Qual Gesundhwes. 2012;106(9):670-6. doi: 10.1016/j.zefq.2012.10.015. Epub 2012 Nov 3.
In the GRADE approach, randomized trials are classified as high quality evidence and observational studies as low quality evidence but both can be rated down if a body of evidence is associated with a high risk of publication bias. Even when individual studies included in best-evidence summaries have a low risk of bias, publication bias can result in substantial overestimates of effect. Authors should suspect publication bias when available evidence comes from a number of small studies most of which have been commercially funded. A number of approaches based on examination of the pattern of data are available to help assess publication bias. The most popular of these is the funnel plot; all, however, have substantial limitations. Publication bias is likely frequent, and caution in the face of early results, particularly with small sample size and number of events, is warranted.
在GRADE方法中，随机试验被归类为高质量证据，观察性研究为低质量证据，但如果一组证据存在较高的发表偏倚风险，两者的质量等级都可能下调。即使纳入最佳证据总结的个别研究偏倚风险较低，发表偏倚也可能导致对效应的大幅高估。当现有证据来自许多大多由商业资助的小型研究时，作者应怀疑存在发表偏倚。有多种基于数据模式检查的方法可用于帮助评估发表偏倚。其中最常用的是漏斗图；然而，所有这些方法都有很大的局限性。发表偏倚可能很常见，面对早期结果时应谨慎，尤其是样本量小和事件数量少的情况。
