Article type
Year
Abstract
Background: The GRADE (Grading of Recommendations Assessment, Development, and Evaluation) tool allows systematic appraisal of the quality of a body of evidence based on specific domains leading to an overall score assessment presented in 'Summary of findings' tables (SoFs).
Objectives: To survey the level of evidence contributing to recommendations derived from Cochrane Reviews and how this level of evidence correlates with whether an intervention is recommended or not.
Methods: All systematic reviews on the Cochrane Database of Systematic Reviews (CDSR) from 1 January 2013 to 30 June 2014 were identified and selected by two authors from the Cochrane Library. Data were extracted independently by two authors and the quality of the evidence for the first listed primary outcome in SoFs in each review and reasons for upgrade or downgrade were recorded. For reviews with high quality of evidence, those with low quality of evidence, and a random sample of 50 reviews with no GRADE assessment, we also extracted the results for the evaluated outcomes and recommendations for the use of interventions.
Results: A total of 1394 SRs were identified; 608 (43.6%) of these incorporated GRADE. Within these reviews 13.5%, 30.8%, 31.7% and 24.0% reported high, moderate, low and very low levels of evidence, respectively, for the evaluated primary outcome. High level quality was more common in updated than new reviews and for pharmacological than other types of interventions. Even when all outcomes listed in the SoFs were considered, only 116/608 (19.1%) SRs had at least one outcome with a high quality of evidence. Twenty-five (30.5%) of 82 SRs with high quality evidence had both significant results and interventions recommended by the authors.
Conclusions: A minority of systematic reviews in the CDSR have high level evidence and even in this small set, an intervention was recommended in only one-third of the reviews.
Objectives: To survey the level of evidence contributing to recommendations derived from Cochrane Reviews and how this level of evidence correlates with whether an intervention is recommended or not.
Methods: All systematic reviews on the Cochrane Database of Systematic Reviews (CDSR) from 1 January 2013 to 30 June 2014 were identified and selected by two authors from the Cochrane Library. Data were extracted independently by two authors and the quality of the evidence for the first listed primary outcome in SoFs in each review and reasons for upgrade or downgrade were recorded. For reviews with high quality of evidence, those with low quality of evidence, and a random sample of 50 reviews with no GRADE assessment, we also extracted the results for the evaluated outcomes and recommendations for the use of interventions.
Results: A total of 1394 SRs were identified; 608 (43.6%) of these incorporated GRADE. Within these reviews 13.5%, 30.8%, 31.7% and 24.0% reported high, moderate, low and very low levels of evidence, respectively, for the evaluated primary outcome. High level quality was more common in updated than new reviews and for pharmacological than other types of interventions. Even when all outcomes listed in the SoFs were considered, only 116/608 (19.1%) SRs had at least one outcome with a high quality of evidence. Twenty-five (30.5%) of 82 SRs with high quality evidence had both significant results and interventions recommended by the authors.
Conclusions: A minority of systematic reviews in the CDSR have high level evidence and even in this small set, an intervention was recommended in only one-third of the reviews.