Background: Effective recruitment to randomised controlled trials is critically important for a robust, trustworthy evidence base in palliative care. Many trials fail to achieve recruitment targets, but the reasons for this are poorly understood. Understanding barriers and facilitators is a critical step in designing optimal recruitment strategies.
Aim: To identify, explore and synthesise knowledge about recruitment barriers and facilitators in palliative care trials using the '6 Ps' of the 'Social Marketing Mix Framework'.
Design: A systematic review with narrative synthesis.
Data sources: Medline, CINAHL, PsycINFO and Embase databases (from January 1990 to early October 2016) were searched. Papers included the following: interventional and qualitative studies addressing recruitment, palliative care randomised controlled trial papers or reports containing narrative observations about the barriers, facilitators or strategies to increase recruitment.
Results: A total of 48 papers met the inclusion criteria. Uninterested participants (Product), burden of illness (Price) and 'identifying eligible participants' were barriers. Careful messaging and the use of scripts/role play (Promotion) were recommended. The need for intensive resources and gatekeeping by professionals were barriers while having research staff on-site and lead clinician support (Working with Partners) was advocated. Most evidence is based on researchers' own reports of experiences of recruiting to trials rather than independent evaluation.
Conclusion: The 'Social Marketing Mix Framework' can help guide researchers when planning and implementing their recruitment strategy but suggested strategies need to be tested within embedded clinical trials. The findings of this review are applicable to all palliative care research and not just randomised controlled trials.
Keywords: Palliative care; palliative medicine; randomised controlled trial; terminal care.