Effective interventions to increase representation of under-served groups in randomised trials in UK and Ireland: a scoping literature review.

ABSTRACT

Background: Participants in clinical trials often do not reflect the populations that could benefit from the treatments being investigated. There are known barriers to trial participation for under-served groups, but limited evidence on strategies to alleviate these barriers to improve representation. This scoping review aimed to identify effective interventions and design features that improve the representation `of under-served groups in trials, focusing on the UK and Ireland. Methods: We included methodological research studies that reported interventions to improve representation of ethnic minority groups, socioeconomically disadvantaged groups, older people, or those with impaired capacity to consent to randomised controlled trials, conducted in the UK and Ireland, published between 2000-2021. Systematic searches were conducted in November 2021 and data were independently extracted by two authors and narratively synthesised. Results: Seven studies were included one randomised controlled study embedded in five trials, one mixed-methods study, and five studies reporting 'lessons learnt' from one trial. We categorised the 47 reported interventions or strategies into nine broad themes Recruitment sites, recruitment settings, community engagement, and communication with participants, incentives, inclusion criteria, flexibility, patient documentation, and the consent process. Only 28/47 interventions were evaluated, 23 of which were comparison of recruitment pathways.The randomised study found that a £100 incentive mentioned in the invitation letter increased positive responses overall across drug trials in cardiovascular disease and hypertension, but not for older people or those living in the most deprived areas. Invitation letters via GPs and working with communities were reported as successful recruitment pathways in recruiting different under-served populations. Conclusions: Interventions aiming to improve the recruitment of under-served groups in the UK and Ireland were reported across seven papers, but their effectiveness was rarely rigorously evaluated. Included studies were context specific. Using a variety of recruitment methods is likely to help achieve a more diverse cohort.

Not all people are included in medical research, even though they should be. This is especially true for people from certain groups, called 'under-served groups', and there has been a recent focus on improving inclusion of these groups in clinical trials. Researchers have developed tools to help plan studies that include under-served groups. These tools help researchers to consider who should be included in a study, identify barriers to including certain groups, and develop strategies to overcome those barriers. A team of researchers reviewed existing research to see what strategies have been successful in increasing the participation of under-served groups in clinical trials in the UK and Ireland. They looked at ethnic minority groups, people experiencing disadvantages in income, education, housing and/or employment (socioeconomic disadvantage), older people, and people with limited decision-making abilities (impaired capacity to consent). They found seven studies that provided helpful insights. Two of these studies were designed specifically to test different methods for recruiting under-served groups. The other five studies were based on lessons learned from trials that included these groups. One study found that offering a £100 incentive in recruitment letters led to an increase in responses, but not specifically for older people or people experiencing socioeconomic disadvantage. Another study found that letters from general practitioners were most effective for recruiting older adults. One study found that community engagement was successful for recruiting an ethnic minority group. Overall, the review concluded that there is little evidence for strategies that will increase the inclusion of under-served groups in clinical trials in the UK and Ireland. However, there are several promising approaches that could overcome barriers and make research more inclusive.