GRADE guidelines: 5. Rating the quality of evidence-publication bias.

Overview

Title:

GRADE guidelines: 5. Rating the quality of evidence-publication bias.

Authors:

Guyatt GH, Oxman AD, Montori V, Vist G, Kunz R, Brozek J, Alonso-Coello P, Djulbegovic B, Atkins D, Falck-Ytter Y, Williams JW Jr, Meerpohl J, Norris SL, Akl EA, Schünemann HJ

Journal:

J Clin Epidemiol.

Publication date:

2011 Jul 29

Volume:

Epub ahead of print

Link to pubmed:

http://www.ncbi.nlm.nih.gov/pubmed/21802904

Publication type:

Journal

Abstract

In the GRADE approach, randomized trials start 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.

Preview

GRADE guidelines: 5. Rating the quality of evidence-publication bias. Guyatt GH, Oxman AD, Montori V, Vist G, Kunz R, Brozek J et al. J Clin Epidemiol. 2011 Jul 29; Epub ahead of print:.