Opportunities and challenges to delivering a trial for depressive symptoms in primary care during the COVID-19 pandemic: insights from the Alpha-Stim-D randomised controlled trial.

Background: Randomised controlled trials (RCTs) are widely regarded as the most powerful research design for evidence-based practice. However, recruiting to RCTs can be challenging resulting in heightened costs and delays in research completion and implementation. Enabling successful recruitment is crucial in mental health research. Despite the increase in the use of remote recruitment strategies and digital health interventions, there is limited evidence on methods to improve recruitment to remotely delivered mental health trials. The paper outlines practical examples and recommendations on how to successfully recruit participants to remotely delivered mental health trials.

Methods: The Alpha Stim-D Trial was a multi-centre double-blind randomised controlled trial, for people aged 16 years upwards, addressing depressive symptoms in primary care. Despite a 6-month delay in beginning recruitment due to the COVID-19 pandemic, the trial met the recruitment target within the timeframe and achieved high retention rates. Several strategies were implemented to improve recruitment; some of these were adapted in response to the COVID-19 pandemic. This included adapting the original in-person recruitment strategies. Subsequently, systematic recruitment using postal invitations from criteria-specific search of the sites' electronic health records was added to opportunistic recruitment to increase referrals in response to sub-target recruitment whilst also reducing the burden on referring sites. Throughout the recruitment process, the research team collaborated with key stakeholders, such as primary care clinicians and the project's Patient and Public Involvement and Engagement (PPI/E) representatives, who gave advice on recruitment strategies. Furthermore, the study researchers played a key role in communicating with participants and building rapport from study introduction to data collection.

Conclusions: Our findings suggest that trial processes can influence recruitment; therefore, consideration and a regular review of the recruitment figures and strategies is important. Recruitment of participants can be maximised by utilising remote approaches, which reduce the burden and amount of time required by referring sites and allow the research team to reach more participants whilst providing participants and researchers with more flexibility. Effectively communicating and working collaboratively with key stakeholders throughout the trial process, as well as building rapport with participants, may also improve recruitment rates.