Evaluation of Research Contributions to Vascular Group of Cochrane Systematic Reviews: 13-Year Analysis from 1998 to 2021

Purpose: Cochrane systematic reviews are widely considered to be among the highest level of evidence available with their conclusions often impacting medical policy and practice. Some countries are reported to have a disproportionately higher representation in their authorship, but it is unclear which regions have contributed the most. This study aims to evaluate authorship patterns in the vascular group of Cochrane systematic reviews.

Materials and Methods: Metadata from the Cochrane Database for Systematic Reviews published under the Cochrane Vascular Group from October 1998 to October 2021 were extracted and analyzed. Both active reviews and withdrawn reviews were evaluated in the analysis. The data collected included year of publication as well as the country of origin of all coauthors and the corresponding author.

Results: A total of 181 eligible reviews were found, authored by a total of 749 authors. Coauthors disproportionately belonged to the United Kingdom (43.5%) followed by the Netherlands (8.9%), Brazil and China (7% each), Canada (5.2%), Italy (4.1%), and the rest. Lead authors belonged to United Kingdom (50.8%) followed by Brazil (7.7%), the Netherlands (7.1%), China (5%), and Italy (4.4%). Countries or regions that otherwise contribute actively to the vascular literature but otherwise had little to no representation included all of Africa, Pakistan, Russia, Mexico, and France. Authors from United States had a very small contribution to the vascular group (2.6%) of Cochrane reviews compared with other groups such as urology (30.5%).

Conclusions: Researchers from the United Kingdom are the biggest contributors to the highest quality evidence in vascular disease (approximately six times more than the next highest contributing region), consistent with citation analysis of the vascular literature. Capacity-building efforts are needed in other countries for improving global vascular specialist involvement with Cochrane systemic reviews and presenting widely representative data.