Preference-based quality of life in patients with Alzheimer's disease

This study was developed to evaluate the feasibility, reliability, and validity of use of patients' ratings of health preference measures as outcomes for cost-effectiveness analyses in persons with very mild to moderate Alzheimer's disease (AD).

Patients and caregivers completed ratings of the EuroQol-5D system (EQ-5D) and the Health Utilities Index Mark 2 (HUI2) and instruments that assess cognition, mood, insight, AD-specific and generic health-related quality of life (QOL) and activities of daily living.

Patients' HUI2 scores were reliable. EQ-5D scores were somewhat less so. Patients rated their utility high, with overall EQ-5D and HUI2 scores greater than 0.8. Neither the EQ-5D nor the HUI2 scores had a relationship with severity of cognitive impairment. Both the EQ-5D and the HUI2 had expected relationships with patient-rated measures of QOL, function, mood, and specific subscales we hypothesized should be associated with patient preferences. Patient insight into functional and cognitive impairments had little association with their health preference scores.

AD patients' scores on the EQ-5D and the HUI2 have many of the characteristics of valid preference measures. However, the proportions of persons who do not perceive any disability, the lack of association with the caregivers' ratings of activities of daily living, limited associations with insight, and no association with their Mini-Mental State Exam scores suggest that patients' reports of disability might reflect legitimate self-perceptions of mood and function that are associated with comorbidities rather than with AD.