Recruitment and Retention of Older People in Clinical Research: A Systematic Literature Review.

Objective: To identify barriers and solutions for the recruitment and retention of older (aged ≥65 years) people in clinical trials.

Design: Systematic literature review.

Methods: Three databases (Medline, Embase, and CENTRAL) were searched for articles reporting on barriers or solutions regarding the recruitment or retention of older people. Only original research articles were included.

Results: Fifty eligible articles were identified. Exclusion criteria were the most common cause of poor recruitment of older adults (mainly age and comorbidities). Patients' families or physicians often advised against participation (22% of included studies). Lack of interest (18%) and problems with transportation (18%) were also commonly cited as challenges. Fourteen trials (28%) reported that monitoring and adapting their recruitment methods helped, along with a flexible research team (26%) and provision of transportation (24%). Retention was impaired by death (12%), illness (8%), and loss of interest (6%). Methods with a positive effect on retention included financial incentives and regular information about the progress of the study (12%), a low staff turnover (12%), flexibility in appointment making (10%), and expression of appreciation by the staff through letters, gifts, and cards to the participants (10%).

Conclusion: We identified several barriers and have listed potential solutions that may improve recruitment and lead to fewer dropouts in trials involving older populations. Implementation of our findings may help mitigate the manifold challenges that come with running a trial with older people.