The use of proxy respondents in studies of older adults: Lessons, challenges, and opportunities

OBJECTIVE: Proxies play a critical role as sources of health information for older persons with cognitive impairment and other chronic debilitating conditions. This paper reviews the validity of proxy responses for people older than age 60 in the following areas: functioning, physical and mental health, cognition, medical care utilization, and preferences for types of care and health states. DESIGN: A Medline review identified 24 clinical studies from 1990 to 1999 that use proxy data as a source of information about older adults. RESULTS: In general, studies report fairly good agreement between subjects and proxies in assessments of functioning, physical health, and cognitive status, and fair-to-poor agreement in assessments of psychological well-being. Proxies tend to describe more impairment in functioning and emotional well-being, relative to subjects, a pattern that is particularly marked among persons with cognitive impairment. In addition, proxies who report more caregiver responsibilities and subjective stress from caregiver duties provide more negative assessments of subjects' health and well-being. CONCLUSIONS: Findings tend to support the use of proxy ratings among older adults in many areas but not all when self-reports are not feasible. There is a need for more evaluation of proxy data in relation to other measures, such as performance assessments, medical records, and claims data, which may be less subject to respondent biases.