Recruiting ENT and Audiology patients into pharmaceutical trials: evaluating the multi-centre experience in the UK and USA

<i>Objective</i>: Recruiting into clinical trials on time and on target is a major challenge and yet often goes unreported. This study evaluated the adjustment to procedures, recruitment and screening methods in two multi-centre pharmaceutical randomised controlled trials (RCTs) for hearing-related problems in adults. <i>Design</i>: Recruitment monitoring and subsequent adjustment of various study procedures (e.g. eligibility criteria, increasing recruiting sites and recruitment methods) are reported. Participants were recruited through eight overarching methods: trial registration, posters/flyers, print publications, Internet, social media, radio, databases and referrals. The efficiency of the recruitment was measured by determining the number of people: (1) eligible for screening as a percentage of those who underwent telephone pre-screening and (2) randomised as a percentage of those screened. <i>Study sample</i>: A total of 584 participants completed the pre-screening steps, 491 screened and 169 participants were randomised. <i>Results</i>: Both RCTs completed adjustments to the participant eligibility, added new study sites and additional recruitment methods. No single recruitment method was efficient enough to serve as the only route to enrolment. <i>Conclusion</i>: A diverse portfolio of methods, continuous monitoring, mitigation strategy and adequate resourcing were essential for achieving our recruitment goals.