Many randomized controlled trials (RCTs) are conducted each year but only a small proportion is specifically designed for Indigenous people. In this review we consider the challenges of participation in RCTs for Indigenous peoples from New Zealand, Australia, Canada and the United States and the opportunities for increasing participation.

The literature was systematically searched for published articles including information on the barriers and facilitators for Indigenous people’s participation in health-related RCTs. Articles were identified using a key word search of electronic databases (Scopus, Medline and EMBASE). To be included, papers had to include in their published work at least one aspect of their RCT that was either a barrier and/or facilitator for participation identified from, for example, design of intervention, or discussion sections of articles. Articles that were reviews, discussions, opinion pieces or rationale/methodology were excluded. Results were analysed inductively, allowing themes to emerge from the data.

Facilitators enabling Indigenous people’s participation in RCTs included relationship and partnership building, employing Indigenous staff, drawing on Indigenous knowledge models, targeted recruitment techniques and adapting study material. Challenges for participation included both participant-level factors (such as a distrust of research) and RCT-level factors (including inadequately addressing likely participant barriers (phone availability, travel costs), and a lack of recognition or incorporation of Indigenous knowledge systems.

The findings from our review add to the body of knowledge on elimination of health disparities, by identifying effective and practical strategies for conducting and engaging Indigenous peoples with RCTs. Future trials that seek to benefit Indigenous peoples should actively involve Indigenous research partners, and respect and draw on pertinent Indigenous knowledge and values. This review has the potential to assist in the design of such studies.