A systematic review of discontinued trials suggested that most reasons for recruitment failure were preventable

Area of Science:

• Clinical Trials
• Research Methodology

Background:

• Recruitment failure is a significant cause for the discontinuation of randomized controlled trials (RCTs).
• Understanding the reasons behind recruitment failure is crucial for improving future trial design and success rates.

Purpose of the Study:

• To systematically collect and categorize reported reasons for recruitment failure in discontinued RCTs.
• To evaluate the quality of reporting regarding recruitment challenges in published RCTs.

Main Methods:

• A systematic literature search was conducted on MEDLINE and EMBASE databases for RCTs discontinued due to poor recruitment between 2010 and 2014.
• Information was extracted by two independent investigators using standardized forms, and reasons for recruitment failure were classified through an iterative approach.

Main Results:

• Out of 172 included RCTs, 131 (76%) reported reasons for discontinuation due to recruitment failure.
• Twenty-eight distinct reasons were identified, with the most frequent being overestimation of eligible participant prevalence and negative perceptions of trial interventions.
• Reporting on key recruitment process details, such as participant identification and screening numbers, was often inadequate.

Conclusions:

• The developed classification system can serve as a checklist to aid investigators in planning RCTs.
• Many recruitment failures appear preventable, suggesting the utility of pilot studies incorporating planned informed consent procedures.