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

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.