Recruitment strategies in randomised controlled trials of men aged 50 years and older: a systematic review

Objectives To identify and review evaluations of strategies to recruit men aged 50 years and over to randomised controlled trials (RCTs). Design Systematic review and narrative synthesis. Data sources MEDLINE, EMBASE, CINAHL and ORRCA databases were searched to 1 December 2017. Eligibility criteria Studies using quantitative methods to evaluate recruitment strategies to RCTs of men aged 50 years and older. Data extraction and synthesis A single reviewer extracted data (for each strategy, number of participants approached, screened and randomised, and cost). Study quality was assessed using National Heart, Lung and Blood Institute Quality Assessment Tools and considered study design, description of interventions, description and measurement of outcomes, completeness of outcome reporting, performance of statistical testing and consideration of confounders. Recruitment strategies were categorised by the recruitment stage they addressed. Results Sixteen studies (n >14 000) were included: one good quality, ten fair quality and five poor quality. Studies evaluated strategies to identify prospective participants, and to improve the processes for assessing participant eligibility, providing participant information and seeking consent. In good and fair quality studies, the most effective strategies for identifying participants were referral from an affiliated health service provider (two studies), mass mailing (five studies) and media coverage (two studies). Community outreach activities such as displaying posters and attending local community events were not effective (two studies). Trial-specific training of site recruitment staff, developed using qualitative analysis of recruitment visits (two studies), and provision of study information to prospective participants at a multidisciplinary, group information session (one study) both improved recruitment. Conclusion Improved engagement of men aged 50 years and older in RCTs is needed. A gender-sensitised approach to RCT recruitment may help to address this need. We have identified several promising recruitment strategies that merit further evaluation. PROSPERO registration number CRD42017060301.