Factors influencing enrollment and retention of older adults in longitudinal clinical research.

摘要

Introduction. Historically, older adults have been under-represented in cancer and heart disease research studies. Although methods of recruitment and retention have been studied in general, very few studies have examined this in older populations.; Objective. To determine factors influencing enrollment and retention of older adults in longitudinal clinical research studies.; Design. Cross-sectional survey of potential participants of the Alzheimer's Disease Anti-inflammatory Prevention Trial (ADAPT), a primary prevention trial that enrolled adults aged 70+ years. An analysis of retention of participants in the Cardiovascular Health Study (CHS), a cohort study that enrolled adults aged 65+ years.; Methods. Potential participants of ADAPT were surveyed about their interest in the trial, and if eligible, what factors influenced their decision to join the trial using two self-administered questionnaires. Frequencies of question responses were determined. Participants who were eligible for ADAPT but refused to enroll were compared to participants who enrolled in ADAPT using logistic regression techniques.; Retention of older adults in a cohort study was analyzed in two ways. First, participants who missed one visit and participants who missed two or more visits were compared to participants who completed all visits using multinomial logistic regression. Second, participants who dropped out of CHS were compared to participants who completed the last follow-up visit using logistic regression.; Results. Factors influencing enrollment in ADAPT were altruism, personal benefit, and family history of Alzheimer's disease, as determined from the survey results provided by 402 enrolled participants of ADAPT. During recruitment in ADAPT, 43 (5.7%) eligible participants refused to enroll in the trial. These refusers had lower Karnofsky performance status scores.; During CHS, 834 (14.4%) participants missed at least one visit and 402 (6.9%) dropped out of the study. Participants who did not complete CHS follow-up visits were more likely to be older, married, and former or current smokers. Also, these participants reported lower annual income, and fair or poor health.; Conclusion. Health status at baseline appears to be associated with both enrollment and retention. When planning recruitment and retention strategies for older adults, special consideration, such as home visits, is warranted for participants who are experiencing failing health.