Meta-epidemiology and reporting characteristics of mapping reviews: a scoping review

Objectives: To investigate the meta-epidemiology and reporting characteristics of mapping reviews.

Study design and setting: We conducted a scoping review of a sample of recent mapping reviews (2022-2023) by searching nine electronic databases and eleven institutional websites up to January 2024. A 28-item reporting checklist, developed by our team and based on existing guidance and methodological studies of mapping reviews, was employed to assess reporting characteristics. The median (interquartile range, IQR) was calculated based on the number of studies that reported each specified reporting item.

Results: A total of 451 mapping reviews were included, with 197 published in 2022 and 254 in 2023. The USA published the most studies (80, 17.74%) and the University of London being the most active institution (23, 5.10%). Barbosa JLV from Universidade do Vale do Rio dos Sinos authored the highest number of studies, with significant collaborations primarily between Chinese and Canadian teams. The studies spanned 11 fields within health and social sciences, Environmental Evidence and Campbell Systematic Reviews published the most studies. A random sample of 200 studies was further assessed for reporting characteristics, where items such as title, author, abstract, background, conclusions, acknowledgements, contributions of authors, declarations of interest, and sources of support were reported by over 50% of the studies. Median number of studies reporting items related to methods, results, and discussion was 89.5 (IQR: 45.5, 165.25), 94.0 (IQR: 61.5, 183.5), and 164 (IQR: 124.0, 179.25) respectively. Items such as the definition of stakeholders, registration information, deviations from protocol, strategy for adequacy and priority setting, and plans for map updates were reported by less than 20% of the studies.

Conclusion: Mapping reviews receive contributions from authors across various countries and institutions. However, collaboration between teams is limited, and the reporting of included studies, especially in the methods and results sections, needs improvement to better emphasize their unique attributes and functions compared to other methods.