A scoping review of interventions intended to reduce publication bias in randomised trials

Abstract

Abstract Background The World Health Organization recommends that a randomised controlled trial (RCT) publishes its results in a peer-reviewed journal within 24 months of study completion. When RCTs are not published or publication is delayed, this is publication bias. There is uncertainty about which interventions best mitigate publication bias. This review systematically synthesises literature on interventions targeting researchers to reduce publication bias among health science researchers. Methods We conducted a comprehensive search in PubMed and Scopus, and forward and backward citation searches. There were no restrictions on language, time or publication status. We included studies of any design that tested an intervention to reduce publication bias in health research. Ideally, participants had to be investigators or researchers who had conducted, led or been involved in RCTs. The context was any research institution that conducts research. Two reviewers independently assessed titles and abstracts for eligibility, followed by duplicate full-text screening and data extraction. One reviewer collated and summarised the extracted data and arranged these using an analytical framework to describe the findings thematically. For quality assurance, a second reviewer checked the data analysis. Results Our database search yielded 14,185 records, with 11,754 after de-duplication. Of these, we excluded 11,728 records after title and abstract screening. We assessed 26 full texts for eligibility. One of these met the eligibility criteria. Forward and backward citation searches yielded 57 records, 43 were eligible. We included 44 studies published between 1995 and 2022 that described interventions promoting the publication of health-related research. We identified ten broad interventions that were often used in combination and concentrated on writing manuscripts. Discussion This review describes several strategies used to assist researchers in publishing their RCT findings. Despite high rates of publication bias and its substantial impact on research waste, we found no research explicitly targeting interventions to encourage trialists to publish their results. Rigorous research is needed to determine effective strategies for reducing publication bias among trialists.