Determinants of Non-Compliance and Attrition in the Elderly

BACKGROUND: This report identifies demographic and health-related baseline factors associated with non-compliance and attrition in elderly subjects participating in a preventive intervention study over a 4-year follow-up period. METHODS: The Cox proportional hazards model and polychotomous logistic regression were used to evaluate time to clinic assessment non-compliance and type of non-participation. RESULTS: Of 1785 subjects, 35.6 percent were non-compliant during follow-up which meant they were eligible to participate at the time they were contacted but would not or could not return for an assessment. Refusals due to a lack of continuing interest or being too busy,and those citing health problems constituted the major subgroups of non-compliers. Death, unable to contact, and ineligible due to disenrollment or moving away accounted for nearly 20 percent. Four-year compliance was achieved by 44.4 percent of the participants. Time to non-compliance was significantly shorter with older age, lower annual income, poorer personal health ranking, and, to a marginal extent, depression. Lower annual income was associated with all reasons for non-participation including disenrollment or moving. Other factors correlated with specific types of nonparticipation. CONCLUSIONS: These results can be useful in designing more effective cohort maintenance strategies. Greater resources may be allocated to subgroups who are less likely to continue.