Recruitment to randomised studies

Maintaining adequate and consistent accrual of patients is important for small clinical trials and crucial to large multicentre, multinational clinical trials, in which participants often number in the thousands. Trial recruitment that is slower than expected can result in prolonged trial durations, increased costs, uneven workload, and morale problems, both for trial participants and trialists.1 Furthermore, when recruitment is so poor that it needs to be curtailed before the trial's target sample size is reached, study power is reduced and there may be a need to revise study endpoints.2