Article type
Year
Abstract
Background: Overviews of systematic reviews aim to primarily search for, retrieve, and synthesise the results of systematic reviews. For topic areas with a large volume of literature and breadth of scope, overviews serve as an efficient way to synthesise the evidence. Research is needed to understand the scope and trend in overviews published annually and to identify factors that may influence the incidence of publication.
Objectives: The purpose of this study is to evaluate the epidemiology and characteristics of overviews of systematic reviews (overviews) including the number of overviews published per year and the annual proportion of overviews among all published studies, and evaluate trends over time.
Methods: We searched MEDLINE (Ovid), Epistemonikos and the Cochrane library databases from 2000 to December 2018. Inclusion criteria: a) overviews that had a methods section and described a systematic literature search in the body of the paper, b) examined the effects of a health intervention, c) published in any language and d) aimed to primarily synthesise systematic reviews. Articles were extracted independently by multiple reviewers, compared, and then triple checked by the lead investigator. We extracted the medical field of the overview; year of publication; country and continent of the corresponding author; number of authors (1, 2-3, 4-5, 6-10, more than 10); journal of publication; number of included studies; number of patients total in the systematic reviews; the time required to conduct each overview; inclusion of meta-analysis; funding status; and funding type.
To determine the global trend in overview publications between 2000 and 2018 the annual number of overviews published worldwide was calculated and presented in a line graph. Number of overviews published per year were stratified by journals and continents. We also assessed the number of duplicate overviews on similar topics.
Results: From a total of 9917 records retrieved from Ovid MEDLINE, Cochrane Database of Systematic Reviews, and Epistemonikos databases, as well as 237 records retrieved from other sources, 1688 duplicates were removed. Of the remaining 8220 records, 7663 were excluded. In total, 557 overviews were included. Over half of publications were from European authors. In total, 65% of the overviews were published after the start of 2013, and 53% between 2015 and 2018. Only 43% of the overviews reported funding sources. The most common medical field of focus overall was diseases of the musculoskeletal system. The overviews were most frequently published in the Cochrane Database of Systematic Reviews and the Sao Paulo Medical Journal.
Conclusions: Our findings demonstrate a rapid increase in the number of overviews published between 2000 and 2018. Overviews should be registered publicly, and authors should avoid duplication of overviews on similar topics to avoid contributing to research waste.
Objectives: The purpose of this study is to evaluate the epidemiology and characteristics of overviews of systematic reviews (overviews) including the number of overviews published per year and the annual proportion of overviews among all published studies, and evaluate trends over time.
Methods: We searched MEDLINE (Ovid), Epistemonikos and the Cochrane library databases from 2000 to December 2018. Inclusion criteria: a) overviews that had a methods section and described a systematic literature search in the body of the paper, b) examined the effects of a health intervention, c) published in any language and d) aimed to primarily synthesise systematic reviews. Articles were extracted independently by multiple reviewers, compared, and then triple checked by the lead investigator. We extracted the medical field of the overview; year of publication; country and continent of the corresponding author; number of authors (1, 2-3, 4-5, 6-10, more than 10); journal of publication; number of included studies; number of patients total in the systematic reviews; the time required to conduct each overview; inclusion of meta-analysis; funding status; and funding type.
To determine the global trend in overview publications between 2000 and 2018 the annual number of overviews published worldwide was calculated and presented in a line graph. Number of overviews published per year were stratified by journals and continents. We also assessed the number of duplicate overviews on similar topics.
Results: From a total of 9917 records retrieved from Ovid MEDLINE, Cochrane Database of Systematic Reviews, and Epistemonikos databases, as well as 237 records retrieved from other sources, 1688 duplicates were removed. Of the remaining 8220 records, 7663 were excluded. In total, 557 overviews were included. Over half of publications were from European authors. In total, 65% of the overviews were published after the start of 2013, and 53% between 2015 and 2018. Only 43% of the overviews reported funding sources. The most common medical field of focus overall was diseases of the musculoskeletal system. The overviews were most frequently published in the Cochrane Database of Systematic Reviews and the Sao Paulo Medical Journal.
Conclusions: Our findings demonstrate a rapid increase in the number of overviews published between 2000 and 2018. Overviews should be registered publicly, and authors should avoid duplication of overviews on similar topics to avoid contributing to research waste.