Background The disconnect between populations reporting poorer health outcomes, such as a higher cardiovascular disease (CVD) burden seen in UK ethnic minority (EM) groups, and those represented in randomised controlled trials (RCT) is well documented.

Aim To identify the proportion of UK CVD RCT which feature criteria for participation that might disproportionately exclude people from ethnic minority groups.

Methods A systematic review of the non-clinical eligibility criteria described in UK CVD RCTs protocols was conducted. MEDLINE, Embase, and the Cochrane Library database were searched. Seventy RCT protocols were included following screening by two reviewers. Data extraction and synthesis were carried out by one reviewer using a form and by tabulating findings, followed by data checking by multiple reviewers. Data analysis was supported by a coding framework developed by reviewers to classify trials according to their potential to limit or aid the participation of EM groups.

Results Over half (61.4%) of the trials featured limiting criteria in the form of consent processes that relied heavily on only written material, and only 8.6% featured alternative consent pathways (such as oral consent). The requirement for English proficiency was present in 22.9% of the studies. Only a few of the trials (4.2%) mentioned the provision of translation services.

Discussion Eligibility criteria which could lead to the exclusion of EM groups appear to be commonly used in UK-based CVD RCTs. This is expressed more explicitly through consenting processes which do not accommodate different literacy levels. Measures which could aid participation were rare. Limiting eligibility criteria featured in CVD RCTs can continue to favour the recruitment of mostly white British participants from middle and higher socioeconomic backgrounds, with implications for the generalisability of the research findings beyond these groups. The majority of study protocols reviewed did not follow guidelines for making trials more inclusive, nor reflect the agenda of funding bodies and institutions that call for inclusivity in trials. Recent guidelines (such as the NIHR-INCLUDE Ethnicity Framework) are yet to be operationalised efficiently in recently published CVD RCTs. This systematic review shows that despite the existence of a higher burden of CVD in EM groups and the calls for inclusivity in trials, most of the studies are designed in a manner that can limit the participation of under-served groups through their eligibility criteria. These findings point to the need for further co-produced research with relevant stakeholders, such as people from EM groups and trialists, to develop strategies for inclusive recruitment.