Do recruitment SWAT interventions have an impact on participant retention in randomised controlled trials? A systematic review.

BACKGROUND: Evidence-based methods for randomised controlled trial recruitment and retention are extremely valuable. Despite increased testing of these through studies within a trial, there remains limited high-certainty evidence for effective strategies. In addition, there has been little consideration as to whether recruitment interventions also have an impact on participant retention. METHODS: A systematic review was conducted. Studies were eligible if they were randomised controlled trials using a recruitment intervention and which also assessed the impact of this on retention at any time point. Searches were conducted through MEDLINE, EMBASE, Cochrane Library, and the Northern Ireland Hub for Trials Methodology Research SWAT Repository. Two independent reviewers screened the search results and extracted data for eligible studies using a piloted extraction form. RESULTS: A total of 7815 records were identified, resulting in 10 studies being included in the review. Most studies (n = 6, 60%) focussed on the information given to participants (n = 6, 60%), with two (20%) focussing on incentives, and two focussing on trial design and recruiter interventions. Due to intervention heterogeneity, none of the interventions could be meta-analysed. Only one study found any statistically significant effect of letters including a photograph (odds ratio: 5.40, 95% CI 1.12-26.15, p = 0.04). CONCLUSION: Assessment of the impacts of recruitment strategies, evaluated in a SWAT, on retention of participants in the host trial remains limited. Assessment of the impact of recruitment interventions on retention is recommended to minimise future research costs and waste.

Methods to improve patient recruitment and retention in stroke trials.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.