Strategies to recruit and retain older adults in intervention studies: a quantitative comparative study.

Recruitment and retention of participants in randomized controlled trials (RCTs) drawn from the older population is challenging, and studies have shown that poor recruitment and retention may lead to biased samples and results. Several strategies to improve the participation of older adults in research are outlined in the literature. The objective was to identify factors associated with participation in an RCT aiming at preventing depressive symptoms and social isolation in a later phase following a stroke, in an older population living in their homes. Strategies to improve participation were applied in the RCT "Lifestyle intervention for older adults in rehabilitation after stroke: development, implementation and evaluation". Quantitative data collected on participants (n=99) and non-participants (n=56) in the trial were compared using statistical analyses. The findings are in line with earlier studies in that the participants were younger (p=0.01) and received less help in the home (p=0.01) than did non-participants. The results differ from earlier studies in that participants had a higher rate of depressive symptoms (participation rate was 57% with HAD depression scale score 0-2, 61% with score 3-4, 62% with score 5-6 and 79% with a score 7 or above). The findings also illustrate a poorer health-related quality of life among the participants in the role physical domain on Short Form-36 (p=0.01). The results indicate that the use of targeted strategies to enhance participation may lead to a less biased sample as well as the inclusion of more subjects who seem to meet the aims of the intervention.