Clinical trial recruitment faces numerous challenges, as highlighted by a recent analysis of the CapaCiTY program, which included three randomized controlled trials (RCTs). The study, a 'study within a trial' (SWAT), aimed to identify feasibility issues and barriers to recruitment across 27 NHS sites. The findings reveal a significant gap between predicted and actual recruitment rates, underscoring the complexities of conducting clinical research in real-world settings.
The CapaCiTY program, focusing on non-drug therapies for chronic constipation in adults, consisted of three trials: CapaCiTY01, CapaCiTY02, and CapaCiTY03. Despite feasibility assessments, sites consistently overestimated their recruitment potential. For instance, CapaCiTY01 randomized 182 participants out of a target of 394 (46%), CapaCiTY02 randomized 65 out of 300 (22%), and CapaCiTY03 randomized 28 out of 114 (24%).
Key Barriers to Recruitment
A telephone survey conducted in 2017 identified several key obstacles. In CapaCiTY01, the primary barrier was a lack of staff resources coupled with high workload. CapaCiTY02 and CapaCiTY03 faced challenges related to study design incompatibility with routine care and a scarcity of suitable participants.
Staffing and Resources
Staffing issues, including long-term sickness, maternity leave, and delays in recruitment, significantly impacted trial progress. Sites often struggled to maintain the minimum staffing requirements outlined in the trial feasibility assessments. The study also found that simply providing Clinical Research Nurse (CRN) support was not enough. Sites with a more integrated model of CRN support, where the CRN nurse was embedded in the one department full time with principal investigator support, were most successful in meeting recruitment targets.
Study Design and Protocol
Incompatibilities between the study protocol and routine clinical practice also posed significant hurdles. For example, in CapaCiTY02, some UK Clinical Commissioning Groups (CCGs) stopped prescribing anal irrigation devices, a key component of the trial, due to perceived insufficient evidence of effectiveness. This led to the withdrawal of sites with potentially high recruitment potential.
Similarly, CapaCiTY03 faced challenges related to the timing of surgical interventions. The protocol required patients to undergo surgery within four weeks of randomization, which was often impractical for NHS sites due to waiting list constraints. Some sites declined to participate due to this challenge, while others viewed the chance for earlier surgery as a positive aspect.
External Factors
Unforeseen external factors further complicated recruitment efforts. In 2016, the NHS faced legal ramifications due to complications from pelvic mesh surgery, which negatively impacted recruitment for CapaCiTY03. Adverse press reporting contributed to a decline in patient enrollment.
Mitigation Strategies and Outcomes
To address these challenges, the research team implemented various strategies, including refresher site initiation visits, investigator meetings, protocol amendments, and advertising campaigns. The follow-up period was shortened from 24 to 12 months, and an electronic data capture system was introduced to reduce the burden on patients and staff. Despite these efforts, the final recruitment achieved was only 34% of the intended sample size. After a 12-month extension, the data monitoring and ethics committee (DMEC) halted the three studies due to futility.
This analysis underscores the importance of realistic feasibility assessments, adequate staffing and resource allocation, and careful consideration of study design compatibility with routine clinical practice. Addressing these factors is crucial for improving recruitment rates and ensuring the success of future clinical trials.
