Patient- and proxy-reported utility in Alzheimer disease using the EuroQoL.

This study aims to compare patient- and proxy-rated utilities and health-related quality of life from individuals in different stages of Alzheimer disease (AD). Two hundred seventy-two patients and their primary caregivers were enrolled in a prospective observational study and underwent three consecutive interviews, 6 months apart. Average Mini-Mental State Examination (MMSE) scores were 19.3, 18.0, and 16.4 at the three interviews; scores ranged from 0 to 30. Using the EuroQoL EQ-5D instrument, patient-rated health utilities were on average 0.833 with little variation across MMSE-based severity levels. Proxy-rated health utilities were 0.69 (MMSE >25), 0.64 (MMSE 21-25), 0.50 (MMSE 15-20), 0.49 (MMSE 10-14), and 0.33 (MMSE <10). Proxy-rated utilities, as well as changes in utilities over time, were significantly related to MMSE scores and inversely related to scores on a brief version of the neuropsychiatric inventory (NPI) and institutionalization. Utilities were highly correlated with the disease-specific quality of life instrument QoL-AD. The study shows that the EuroQoL can be used to rate utilities in Alzheimer disease, but there are important differences between patient- and proxy-ratings.