A systematic assessment of Cochrane reviews and systematic reviews published in high-impact medical journals related to cancer

Ref ID 132
First Author M. Goldkuhle
Journal BMJ OPEN
Year Of Publishing 2018
URL https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5875625/pdf/bmjopen-2017-020869.pdf
Keywords • Oncology
• Non-Cochrane reviews
• Cochrane
Problem(s) • Cochrane reviews more rigorous/higher quality than non-Cochrane reviews
• Unwieldy/ difficult to read
Article Type Empirical
Article Subtype Cross-sectional survey/Methodological systematic review
First Author Country Germany
Checklists • AMSTAR 1
Aim To assess the methodological quality (AMSTAR) of cancer-related systematic reviews published between January 2011 and May 2016 from the Cochrane Library and ten high-impact journals.
Level of Investigation Descriptive
Summary of Findings 346 Cochrane reviews and 215 non-Cochrane systematic reviews were included. Cochrane reviews consistently met more individual AMSTAR criteria, notably with regard to an a priori design (risk ratio (RR) 3.89; 95% CI 3.10 to 4.88), inclusion of the grey literature and trial registries (RR 3.52; 95% CI 2.84 to 4.37) in their searches, and the reporting of excluded studies (RR 8.80; 95% CI 6.06 to 12.78). Cochrane reviews were less likely to address questions of prognosis (RR 0.04; 95% CI 0.02 to 0.09), use individual patient data (RR 0.03; 95% CI 0.01 to 0.09) or be based on non-randomised controlled trials (RR 0.04; 95% CI 0.02 to 0.09). Citation rates of Cochrane reviews were notably lower than those for high-impact journals (Cochrane reviews: mean number of citations 6.52 (range 0–143); high-impact journal systematic reviews: 74.45 (0–652)). The authors highlight that Cochrane reviews are not limited by word count, unlike high-impact journals. This can aid better reporting but Cochrane reviews being longer reports may also contribute to their lower citation rate.
Number of systematic reviews included 561
Number of eligible systematic reviews assessed 1149
Treatment impacted No
Treatment impacted description
Interpretation impacted Not Applicable
Interpretation impacted description