Exploring non-retention in clinical trials: a meta-ethnographic synthesis of studies reporting participant reasons for drop out.

Objectives: To undertake a meta-ethnographic synthesis of findings from primary studies reporting qualitative data that have explored participant-reported factors influencing non-retention within a clinical trial context.

Design: A systematic search and meta-ethnography was conducted for published papers (from 1946 to July 2018) that contained qualitative data from trial non-retainers.

Participants: We identified 11 studies reporting qualitative data from 13 trials. The studies were undertaken between 2008 and 2018. Each study included between 3 and 40 people who had dropped out from a trial, with findings from 168 people in total reported across the papers.

Results: Emergent from our synthesis was the significance of trial non-retainers' perceptions around the personal 'fit' of key aspects of the trial with their personal beliefs, preferences, capabilities or life circumstances. These related to their own health state; preferences for receiving trial 'care'; individual capabilities; beliefs about or experiences of trial medication and considerations whether trial participation could be accommodated into their broader lives. All these factors raise important issues around the extent to which initial decisions to participate were fully informed.

Conclusions: To improve retention in clinical trials, researchers should work to reduce the burden on trial participants both through the design of the intervention itself as well as through simplified data collection processes. Providing more detail on the nature of the trial interventions and what can be expected by 'participation' at the consenting stage may prove helpful in order to manage expectations.