Journal article
The quality of evidence for medical interventions does not improve or worsen: a metaepidemiological study of Cochrane reviews.
- Howick J Faculty of Philosophy, University of Oxford, Oxford OX2 6GG, UK. Electronic address: jeremy.howick@philosophy.ox.ac.uk.
- Koletsi D Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
- Pandis N Department of Orthodontics and Dentofacial Orthopedics, School of Dental Medicine, Medical Faculty, University of Bern, Bern, Switzerland.
- Fleming PS Institute of Dentistry, Queen Mary, University of London, London, United Kingdom.
- Loef M CHS-Institute, Berlin, Germany.
- Walach H CHS-Institute, Berlin, Germany; Department of Pediatric Gastroenterlogy, Poznan University of the Medical Sciences, Poznan, Poland.
- Schmidt S Department of Psychosomatic Medicine and Psychotherapy, Medical Center, University of Freiburg, Freiburg, Germany.
- Ioannidis JPA Departments of Medicine, of Epidemiology and Population Health, of Biomedical Data Science, and of Statistics, Meta-Research Innovation Center at Stanford (METRICS), Stanford University, Stanford, CA, USA.
- 2020-09-05
Published in:
- Journal of clinical epidemiology. - 2020
English
OBJECTIVES
The objective of the study was to determine the change in quality of evidence in updates of Cochrane reviews that were initially published between January 1, 2013 and June 30, 2014. We used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system to document evidence quality.
STUDY DESIGN AND SETTING
We searched the Cochrane Database of Systematic Reviews on March 20, 2020 to identify which of the reviews from the initial (2013/14) sample had been updated. Using the same methods to determine the quality of evidence in the previous analysis, we assessed the quality of evidence for the first-listed primary outcomes in the updated reviews.
RESULTS
Of the 608 reviews in the original sample, 154 had been updated with and 151 contained available data for both original and updated systematic reviews (24.8%). The updated reviews included: 15 (9.9%) with high-quality evidence, 56 (37.1%) with moderate-quality evidence, 47 (31.1%) with low-quality evidence, and 33 (21.9%) with very low-quality evidence. No change in the GRADE quality of evidence was found for most (103, 68.2%) of the updated reviews. The quality of evidence rating was downgraded in 28 reviews (58.3%) and upgraded in 20 (41.7%), although only six reviews were promoted to high quality.
CONCLUSION
Updated systematic reviews continued to suggest that only a minority of outcomes for health care interventions are supported by high-quality evidence. The quality of the evidence did not consistently improve or worsen in updated reviews.
The objective of the study was to determine the change in quality of evidence in updates of Cochrane reviews that were initially published between January 1, 2013 and June 30, 2014. We used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system to document evidence quality.
STUDY DESIGN AND SETTING
We searched the Cochrane Database of Systematic Reviews on March 20, 2020 to identify which of the reviews from the initial (2013/14) sample had been updated. Using the same methods to determine the quality of evidence in the previous analysis, we assessed the quality of evidence for the first-listed primary outcomes in the updated reviews.
RESULTS
Of the 608 reviews in the original sample, 154 had been updated with and 151 contained available data for both original and updated systematic reviews (24.8%). The updated reviews included: 15 (9.9%) with high-quality evidence, 56 (37.1%) with moderate-quality evidence, 47 (31.1%) with low-quality evidence, and 33 (21.9%) with very low-quality evidence. No change in the GRADE quality of evidence was found for most (103, 68.2%) of the updated reviews. The quality of evidence rating was downgraded in 28 reviews (58.3%) and upgraded in 20 (41.7%), although only six reviews were promoted to high quality.
CONCLUSION
Updated systematic reviews continued to suggest that only a minority of outcomes for health care interventions are supported by high-quality evidence. The quality of the evidence did not consistently improve or worsen in updated reviews.
- Language
-
- English
- Open access status
- closed
- Identifiers
-
- DOI 10.1016/j.jclinepi.2020.08.005
- PMID 32890636
- Persistent URL
- https://sonar.ch/global/documents/66872
Statistics
Document views: 41
File downloads: