Sinopoulou V, Shah E, Gordon M, Tony-Jimmy TE. Primary author contact for systematic reviews of randomized controlled trials: A systematic review. World J Methodol 2025; 15(3): 95559 [DOI: 10.5662/wjm.v15.i3.95559]
Corresponding Author of This Article
Morris Gordon, MBChB, PhD, Professor, Biomedical Evidence Synthesis and Translation to Practice Unit, School of Medicine, HA340, Harrington Building, 135A Adelphi St, Preston PR1 7BH, United Kingdom. mgordon@uclan.ac.uk
Research Domain of This Article
Methodology
Article-Type of This Article
Systematic Reviews
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
World J Methodol. Sep 20, 2025; 15(3): 95559 Published online Sep 20, 2025. doi: 10.5662/wjm.v15.i3.95559
Primary author contact for systematic reviews of randomized controlled trials: A systematic review
Vasiliki Sinopoulou, Eshan Shah, Morris Gordon, Tonia E Tony-Jimmy
Vasiliki Sinopoulou, Morris Gordon, Biomedical Evidence Synthesis and Translation to Practice Unit, School of Medicine, Preston PR1 7BH, United Kingdom
Eshan Shah, Tonia E Tony-Jimmy, School of Medicine and Dentistry, University of Central Lancashire, Preston PR1 2HE, United Kingdom
Co-first authors: Vasiliki Sinopoulou and Eshan Shah.
Author contributions: Sinopoulou V co-conceived the project idea, led all stages and write-up of the paper, reviewed and approved the final version; Shah E contributed to screening, data extraction, data analysis, and drafting of the final version, reviewed and approved the final version; Gordon M co-conceived the project idea, supervised at all stages of the project, contributed to the writing, reviewed and approved the final version, and is guarantor for the data; Tony-Jimmy TE contributed to screening, data extraction and data analysis, and approved the final version.
Conflict-of-interest statement: The authors declare that they have no conflict of interest.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Morris Gordon, MBChB, PhD, Professor, Biomedical Evidence Synthesis and Translation to Practice Unit, School of Medicine, HA340, Harrington Building, 135A Adelphi St, Preston PR1 7BH, United Kingdom. mgordon@uclan.ac.uk
Received: April 19, 2024 Revised: November 1, 2024 Accepted: December 3, 2024 Published online: September 20, 2025 Processing time: 320 Days and 16.7 Hours
Abstract
BACKGROUND
Systematic reviews (SRs) synthesize and evaluate data, mainly from randomized trials, which then guides the development of clinical recommendations in evidence-based medicine. However, the data and methodological information in the included papers can often be lacking or unclear, and reviewers usually need to contact the authors of included studies for clarifications. Contacting authors is recommended, but it is unclear how often SR teams do it, or what the level of response is.
AIM
To investigate how often reviewers undertake contact with the authors of included randomized controlled trials (RCTs) for clarification on data and risk of bias concerns, to explore the factors that influence whether SR authors contact or do not contact the authors, and the content and level of responses.
METHODS
We conducted a systematic electronic database search in MEDLINE using the search string “(systematic review)” AND “(RCT OR randomized OR trial)” for articles published between 1 January 2024 and 19 February 2024, without language restrictions. Screening and data extraction was done independently by two reviewers, and conflicts resolved by a senior author. Contact authors of included SRs were contacted for clarifications.
RESULTS
Of the 329 included SRs, 38% (n = 125) explicitly mentioned contact with the authors of included studies. The remaining 62% (n = 204) did not. We attempted contact with all SR teams for clarifications and received 90 responses (19.4%). Of the 50 respondents who did not explicitly mention contact in their SRs, 25 (50%) replied that they did make contact. We received a total of 64 responses on the level and content of information sought. The mean ± SD contacts SR teams made were 10 (10), replies received 5 (6.7), and response waiting time 10.1 (28.3) weeks. Resources, time, poor previous experience, perceived likelihood of poor response and bias concerns were reported as barriers to attempting contact.
CONCLUSION
The majority of SRs published in 2024 did not confirm seeking clarifying or missing information from primary study authors. However, SR teams reported that 50% of contacted primary authors respond. Additional research can clarify this rate of response and establish methods to increase the integration of this core methodological element in SRs.
Core Tip: We found that a majority of systematic review teams do not seek clarifying or missing information from primary study authors. Time and resources are seen as a barrier, however, we found that almost 50% of contacted primary authors were reported to respond. Contacting authors should be seen as a core methodological requirement for systematic reviewers, and further steps should be taken to investigate and promote it.
