Social media recruitment enhances participant diversity in dermatology clinical trial: findings from the SAFA trial

Recruitment and retention of participants remain critical challenges in clinical trials, often requiring innovative approaches to ensure sufficient enrolment and sustained engagement. Social media advertising offers the potential to reach target populations quickly by leveraging demographic, geographic and interest-based targeting. This mixed-methods observational study evaluates participant experiences and the effectiveness of various recruitment routes within a trial of a treatment for acne. Demographic variables, including age, ethnicity, acne severity and acne duration, were stratified primary care, secondary care, community and social media recruitment routes and 12 participant interviews were analysed using reflexive thematic analysis. Social media recruitment accounted for over half of participants (53.9%). It was particularly effective in recruiting individuals with higher acne severity (IGA ≥ 3; 57.5% of its recruits, n = 127), longer duration of disease (> 5 years history of acne; 60.2% of its recruits, n = 133) and from ethnic minority groups (9.0% of its recruits, n = 20), the latter being notably higher than the proportion recruited via primary care (1.5% of its recruits, n = 1). Slight variations in retention by recruitment route were observed, with social media (85%) and primary care (84%) achieving the highest retention rate at the 12-week follow-up. All routes lost between 25 and 32% of participants by the 24-week follow-up, signifying the importance of implementing effective retention strategies to keep participants engaged. Overall, participants found targeted social media advertisements to be an acceptable and convenient recruitment approach; initial signals of trust were provided by high-quality graphics and recognisable NHS and university logos, which coupled with responsive trial staff, were suggested to provide a seamless enrolment experience. This study demonstrates that social media recruitment can be an effective and acceptable component of a multi-route strategy for clinical trial enrolment.