Priority 1 Question 13

Study eligibility plays an essential role in trial research as it defines the characteristics of the target populations, and is used for screening and recruitment to trials. Eligibility criteria also influences the generalisability of the trial’s results which are, subsequently, interpreted, implemented, and adapted by different stakeholders. In developing eligibility criteria for selecting study participants, researchers must consider scientific, ethical, regulatory, and safety requirements and translate these into unambiguous eligibility criteria (Kim et al. 2015). However, overly restrictive participant selection can compromise study generalizability and contribute to the difficulty in implementing and disseminating study results to real-world patients across many disease domains (Weng, 2015). An example of this might be an age cut-off exclusion criterion, such as <65years, even though individuals in this age profile might be helpful for answering the trial question. This priority question addresses uncertainty as to how eligibility criteria might be optimised to help recruitment to randomised trials.

• “Perhaps we need to be more pragmatic and so ensure our exclusion criteria are not leading to barriers to recruiting participants that can add value to findings.”
• “More accessible ways of assessing eligibility (an app?) might help”.
• “Are eligibility criteria evidence-based (contraindications to medication etc) or based on assumptions? Should eligibility criteria be harmonised between similar trials to improve meta-analysis (as with outcome measures) to ensure interventions are effective/not in similar populations?”