Methods to improve patient recruitment and retention in stroke trials

The success of randomized-controlled stroke trials is dependent on the recruitment and retention of a sufficient number of patients, but fewer than half of all trials meet their target number of patients.

We performed a search and review of the literature, and conducted a survey and workshop among 56 European stroke trialists, to identify barriers, suggest methods to improve recruitment and retention, and make a priority list of interventions that merit further evaluation.

The survey and workshop identified a number of barriers to patient recruitment and retention, from patients' incapacity to consent, to handicaps that prevent patients from participation in trial-specific follow-up. Methods to improve recruitment and retention may include simple interventions with individual participants, funding of research networks, and reimbursement of new treatments by health services only when delivered within clinical trials. The literature review revealed that few methods have been formally evaluated. The top five priorities for evaluation identified in the workshop were as follows: short and illustrated patient information leaflets, nonwritten consent, reimbursement for new interventions only within a study, and monetary incentives to institutions taking part in research (for recruitment); and involvement of patient groups, remote and central follow-up, use of mobile devices, and reminders to patients about their consent to participate (for retention).

Many interventions have been used with the aim of improving recruitment and retention of patients in stroke studies, but only a minority has been evaluated. We have identified methods that could be tested, and propose that such evaluations may be nested within on-going clinical trials.