Supporting meaningful participation of older people in core outcome set development

The use of core outcome sets (COS) by trials is widely accepted as best practice, aiming to improve research efficiency by enabling comparison and aggregation of results across trials for specific clinical areas.1 A COS is an agreed minimum set of standardized outcomes that should be reported in all trials for a specific clinical area.1 A COS should include only fundamental outcomes, that is, core to evaluating a treatment or intervention, rather than every relevant or important outcome.1, 2 Trials can additionally measure other outcomes.1, 3

Outcomes in a COS should be valid and important for all stakeholders. When developing a COS for hospital deprescribing trials,4 we involved stakeholders that would be affected by the intervention: older patients and their carers; healthcare professionals who care for older people in hospital; hospital managers; and academics researching older people's medicine/deprescribing. We followed COMET (Core Outcome Measures in Effectiveness Trials) guidance for COS development1; this summarizes available methods for COS development but provides limited guidance on how to ensure meaningful involvement of patients, who historically have not been involved in deciding which outcomes should be measured in trials. The INCLUDE framework highlights that older people are often explicitly or implicitly excluded from healthcare research.5 Despite anticipating some barriers to older people's participation in our COS study and addressing these in the study planning, we experienced several challenges to ensuring that the selection of outcomes for the COS included their views. We reflect on these challenges, discuss what worked to address them, and present further refinements that could better support equitable, meaningful participation of older people in COS development. Study registration: COMET (Core Outcome Measures in Effectiveness Trials) database (https://www.comet-initiative.org/Studies/Details/1825).