Table 4 The barriers and facilitators mapped to the protocol design and management theme

Protocol design could be missuited to accessibility requirements. For example, long study visits to research centre difficult for those with mobility limitations [21]. Virtual study visits proved harder for patients who had suffered traumatic brain injury (TBI) due to increased light sensitivity [30]

Innovative recruitment schemes like open access screening programmes, use of patient registries and community outreach programmes helps improve access to hard-to-reach disabled populations [28, 38,39,40]

Personal contact-based recruitment meant disabled groups were less likely to be approached. This was due to recruiters having preconceived ideas that disabled people would be poor candidates e.g. they would find the trial too stressful, dissent, be unable to participate, behave inappropriately, fail to adhere to treatment or create additional challenges for research staff [19, 31,32,33]

Cases of collaboration and co-design were reported to be positive for inclusivity. Examples include involving a stakeholder coordinator that had a personal connection to the research study’s disabled population of interest [34], involving representatives from target populations during question and protocol design [35], and collaboration between research bodies and trusted local groups working on similar goals. This helped build trust, allay concerns, allow knowledge sharing, and increase the number of referral pathways [36, 37]