Identifying the ‘incredible’! Part 2: Spot the difference-a rigorous risk of bias assessment can alter the main findings of a systematic review

Ref ID 258
First Author F. Büttner
Journal BRITISH JOURNAL OF SPORTS MEDICINE
Year Of Publishing 2019
URL https://pubmed.ncbi.nlm.nih.gov/31871014/
Keywords • Risk of bias
• Physiotherapy
Problem(s) • Flawed risk of bias undertaken
• Limited quality assessment or no risk of bias
Article Type Empirical
Article Subtype Inter-rater agreement study
First Author Country Ireland
Aim Firstly to identify and characterise methods of quality assessment or risk of bias assessment used in systematic reviews of sports and exercise medicine up to January 2017. Secondly to examine differences between assessment of methodological quality of included studies and risk of bias assessment of included studies.
Level of Investigation Descriptive
Summary of Findings Conclusions about trial quality present differently depending on the choice of checklist. Almost all (98%) of included systematic review performed quality assessment but risk of bias assessments were infrequently performed. 35% of reviews used a modified or adapted tool. Systematic reviews were simultaneously found to be of high quality and yet of high risk of bias in 9 cases. The authors highlight that modified tools should not be used. A worked example in one systematic review found that the majority of trials in one systematic review were judged to be of high quality according to Downs & Black checklist but using the RoB2 tool, they were also judged to be at 'high overall risk of bias.
Number of systematic reviews included 66
Number of eligible systematic reviews assessed 66
Treatment impacted Yes
Treatment impacted description
Interpretation impacted Yes
Interpretation impacted description The true difference between intervention and control groups may actually be larger than concluded, but we cannot be certain because of a ‘high’ risk of bias across many domains. Due the the influence of bias, therapeutic interventions may be more or less effective than concluded in this systematic review.