Extent and nature of duplication in PROSPERO using COVID-19-related registrations: a retrospective investigation and survey

Posted on 16 January 2023

During the COVID-19 pandemic, the International Prospective Register of Systematic Reviews (PROSPERO) experienced a surge in registrations for COVID-19-related systematic reviews, and duplication of research questions became apparent. CRD researchers Lucy Beresford, Ruth Walker and Lesley Stewart conducted an investigation to explore the extent and reasons for this duplication.

First, PROSPERO forms registered in four topic areas were compared: treatments, epidemiology, rehabilitation, and transmission. Registrations that were similar or identical were evaluated further as ‘duplicates’. Authors of ‘duplicate’ registrations were contacted and asked whether they searched PROSPERO prior to registration, identified similar reviews and, if so, why they continued with their review.

Between March 2020 and January 2021, 1054 COVID-19 reviews related to the four topic areas were registered. 138 ‘duplicate’ records were submitted when at least one very similar protocol was already registered on PROSPERO. Duplication was greatest in reviews evaluating treatments for COVID-19. For example, there were 14 ‘duplicate’ registered reviews evaluating the efficacy of hydroxychloroquine and 7 ‘duplicates’ of tocilizumab.

Of the 138 authors contacted, 37 responses were received. The main reasons given for ‘duplication’ were differences in PICOS or planned analyses, poor quality of previous registrations, and the need to update the evidence owing to the rapid rate of new COVID-19 related research being published.

This research highlights that registration of similar and duplicate systematic reviews related to COVID-19 in PROSPERO occurred frequently. Awareness of research waste is required, and initial checking for similar reviews should be embedded within good review practice.

The study has been recently published in BMJ Open:

Beresford L, Walker R, Stewart L. Extent and nature of duplication in PROSPERO using COVID-19-related registrations: a retrospective investigation and survey. BMJ Open 2022;12:e061862