Health utilities in Alzheimer's disease: a cross-sectional study of patients and caregivers.

OBJECTIVES: Although the broad impacts of Alzheimer's disease (AD) are increasingly recognized, little work has focused on the overall health-related quality of life experienced by Alzheimer's disease patients and their caregivers. The study had two main objectives: (1) to test the feasibility of measuring health utilities in Alzheimer's disease with a generic preference-weighted instrument using proxy respondents and (2) to assess the utility scores of Alzheimer's disease patients (and their caregivers) in different disease stages and care setting.

METHODS: A cross-sectional study of 679 Alzheimer's disease patient/caregiver pairs was conducted at 13 sites in the United States: four academic medical centers, four managed care plans, two assisted living facilities, and three nursing homes. The Health Utilities Index Mark II (HUI:2) questionnaire was administered to caregivers of patients who responded both as proxies for patients and for themselves. Responses to the questionnaire were converted into a global utility score, between 0 and 1, using the HUI:2 multi-attribute utility function.

RESULTS: Global utility scores varied considerably across patients' Alzheimer's disease stage: for the six stages assessed (questionable, mild, moderate, severe, profound, and terminal), mean utility scores were 0.73, 0.69, 0.53, 0.38, 0.27, and 0.14, respectively. In multiple regression analyses, Alzheimer's disease stage was a negative and significant predictor of utility scores for patients; setting did not exert an independent effect. Utility scores for the caregivers were insensitive to patients' Alzheimer's disease stage and setting.

CONCLUSIONS: Patients' Alzheimer's disease stage had a substantial influence on health utilities, as measured by the HUI:2. More research is needed to assess the validity of using proxy respondents.