Evaluation of the Cochrane tool for assessing risk of bias in randomized clinical trials: overview of published comments and analysis of user practice in Cochrane and non-Cochrane reviews

Ref ID 501
First Author L. Jørgensen
Journal SYSTEMATIC REVIEWS
Year Of Publishing 2016
URL https://pubmed.ncbi.nlm.nih.gov/27160280/
Keywords • Cochrane
• Risk of bias
• General medical
Problem(s) • Flawed risk of bias undertaken
Article Type Empirical
Article Subtype Cross-sectional survey/Methodological systematic review
First Author Country Denmark
Aim To assess the use of the Cochrane risk of bias tool using editorial comments published in PubMed, The Cochrane Methodology Register and Google Scholar on the tool's strengths and challenges. An observational study of 100 Cochrane and 100 non-Cochrane reviews from 2014 was also conducted to understand how the tool is applied to both Cochrane and non-Cochrane systematic reviews.
Level of Investigation Descriptive
Summary of Findings The tool was used in all Cochrane reviews (100/100) and was the preferred tool in non-Cochrane reviews (31/100). The tool is often used in ways not recommended such as implementing non-standard domains either as fully new domains or incorporating them into the “other bias” function, which is primarily intended for special situations, e.g. crossover trials. Both strengths and challenges of the Cochrane risk of bias tool were identified from comments. Challenges included: concern whether the chosen domains comprehensively address all threats to validity (for example, including funding as an independent bias domain); difficulties in the subjective interpretation of the tool; modest inter-observer agreement, difficulty in assessing selective reporting of outcomes, terminological ambiguity (i.e. of the terms subjective/objective) and the low proportion of reviews using risk of bias assessments as a basis for sensitivity analyses; challenges in assigning an overall risk of bias to a trial based on risk of bias of single domains to the trial as such.
Number of systematic reviews included 68
Number of eligible systematic reviews assessed 976
Treatment impacted No
Treatment impacted description
Interpretation impacted Not Applicable
Interpretation impacted description