‘Recruitment, recruitment, recruitment’ – the need for more focus on retention: a qualitative study of five trials

Loss to follow-up (attrition) is a frequent problem in clinical trials and can introduce bias or reduce power. So, understanding retention issues and strategies to address these are important. As part of a multi-method project, this qualitative study aimed to explore retention strategies used by trial teams and factors which may influence strategy adoption. A purposive sample of active trials was selected from the UK NIHR HTA portfolio of ongoing trials in 2014/2015. Semi-structured interviews with several trial team members from each trial and supplementary interviews with experienced trial managers explored strategies in collecting clinical outcome data and retaining participants. Interview data were analysed thematically using techniques of constant comparison. Twenty-two semi-structured interviews with trial team members including chief investigators, trial managers, nurses and research administrators revealed strategies used to enhance retention. Some were recognised methods and planned from trial outset whilst others were implemented more responsively. Interviewees placed great value on fostering positive relationships with trial participants to enhance retention. However, these strategies took time which was not always appreciated by the wider trial team or funding bodies. The national focus on recruitment targets in networks posed a challenge to staff and was deemed detrimental to retention. The 'moral compass' of individual researchers relied on their own beliefs and values and research experience and the factors affected their confidence to pursue participant data during follow-up. The role of trial staff and their underlying behaviours influence retention practices and, combined with emphasis on recruitment targets, can be detrimental to motivation and retention activities. There is a need to consider how to train and support trial staff involved in retention practices and recognition of retention from funding bodies and oversight organisations.