Primary author contact for systematic reviews of randomized controlled trials: A systematic review.

backgroundSystematic 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.

aimTo 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.

methodsWe 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.

resultsOf the 329 included SRs, 38% (

conclusionThe 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.