Evolution of international collaborative research efforts to develop non-Cochrane systematic reviews

This research-on-research study describes effortsto develop non-Cochrane systematic reviews (SRs) by analysing demographical and time-course collaborations between international institutions using protocols registered in the International Prospective Register of Systematic Reviews (PROSPERO) or published in scientific journals. We have published an a priori protocol to develop this study. Protocols published in scientific journals were searched in MEDLINE/PubMed and Embase databases using the query terms ‘systematic review’[Title] AND ‘protocol’[Title] from February 2011 to December 2017. Protocols registered at PROSPERO during the same period were obtained by web scraping all non-Cochrane records with a Python script. After excluding protocols with less than 90% fulfilled or duplicated, they were classified as published ‘only in PROSPERO’, ‘only in journals’, or in both ‘journals and PROSPERO’. Results of data and metadata extraction using text-mining processes were curated by two reviewers. Datasets and R scripts are freely available to facilitate reproducibility. We obtained 20,814 protocols of non-Cochrane SRs. While ‘unique protocols’ by re-viewers’ institutions from 60 countries were the most frequent, to prepare ‘collaborative protocols’ a median of 6 (2-150) institutions were involved from 130 different countries. Ranked list of countries involved in overall protocol production were the UK, the U.S., Australia, Brazil, China, Canada, the Netherlands, Germany, and Italy. Most protocols were registered only in PROSPERO. However, the number of protocols published in scientific journals (924) or in both PROSPERO and journals (807) has progressively increased over the last three years. Syst Rev and BMJ Open published more than half of the total protocols. While most productive countries were involved in ‘unique’ and ‘collaborative’ protocols, less productive countries only participated in ‘collaborative’ protocols that were mainly published only in PROSPERO. Our results suggest that although most countries were involved in producing in solitary protocols of non-Cochrane SRs during the study period, it would be desirable to develop new strategies to promote international collaborations, especially with less productive countries.