The score after 10 years of registration of systematic review protocols

Abstract

Background With the exponential growth of published systematic reviews (SR), there is a high potential for overlapping and redundant duplication of work. Prospective protocol registration gives the opportunity to assess the added value of a new study or review, thereby potentially reducing research waste and simultaneously increasing transparency and research quality. The PROSPERO database for SR protocol registration was launched 10 years ago. This study aims to assess the proportion SRs of intervention studies with a protocol registration (or publication) and explore associations of SR characteristics with protocol registration status. Methods PubMed was searched for SRs of human intervention studies published in January 2020 and January 2021. After random-stratified sampling and eligibility screening, data extraction on publication and journal characteristics, and protocol registration status, was performed. Both descriptive and multivariable comparative statistical analyses were performed. Results A total of 357 SRs (2020: n = 163; 2021: n = 194) were included from a random sample of 1267 publications. Of the published SRs, 38% had a protocol. SRs that reported using PRISMA as a reporting guideline had higher odds of having a protocol than publications that did not report PRISMA (OR 2.71; 95% CI: 1.21 to 6.09). SRs with a higher journal impact factor had higher odds of having a protocol (OR 1.12; 95% CI 1.04 to 1.25). Publications from Asia had a lower odds of having a protocol (OR 0.43; 95% CI 0.23 to 0.80, reference category = Europe). Of the 33 SRs published in journals that endorse PROSPERO, 45% did not have a protocol. Most SR protocols were registered in PROSPERO (n = 129; 96%). Conclusions We found that 38% of recently published SRs of interventions reported a registered or published protocol. Protocol registration was significantly associated with a higher impact factor of the journal publishing the SR and a more frequent self-reported use of the PRISMA guidelines. In some parts of the world, SR protocols are more often registered or published than others. To guide strategies to increase the uptake of SR protocol registration, further research is needed to gain understanding of the benefits and informativeness of SRs protocols among different stakeholders. Systematic review registration osf.io/9kj7r/

Perspectives on systematic review protocol registration: a survey amongst stakeholders in the clinical research publication process

“…We used an existing sample of 357 SRs from a previous study to identify researchers who have published interventional SRs in the field of health(care) research and editors from journals in which these SRs were published [ 12 ]. These SRs were published in 2020 and 2021 and covered 63 different medical fields [ 12 ]. Email addresses from corresponding authors and/or first and last authors were collected from Web of Science (WoS).…”

“…Despite all these options, the percentage of SRs that have a registered protocol is still relatively low. Recent studies showed that 17–40% of SRs have a registered or published protocol [ 7 , 9 – 12 ]. There are numerous examples of unplanned duplication [ 13 , 14 ].…”

The role of systemic statins in the inception and healing of apical periodontitis: a systematic review

“…The current systematic review was conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols statement 2020 (PRISMA statement 2020) [ 38 , 39 ] (Supplementary Table 1 , Supplementary table 2 ). The protocol was defined and agreed to by all authors, and it was registered under the International Prospective Register of Systematic Reviews – PROSPERO (registration number CRD42021246231) [ 40 ].…”

Definition, harms, and prevention of redundant systematic reviews

“…A study of 357 systematic reviews about human interventions published in January 2020 and January 2021 showed that of the non-Cochrane reviews, 135 (38%) reviews had a protocol either registered, published, or both. PROSPERO was dominantly used for protocol registration ( n = 129; 96%) [ 33 ]. Only 25% of systematic reviews on COVID-19 treatments were registered in PROSPERO [ 34 ].…”