A Comparison of HU12 and HU13 Utility Scores in Alzheimer's Disease

Abstract

Purpose. The Health Utilities Index (HUI) is a generic, multiattribute, preference-based health-status classification system. The HUI Mark 3 (HU13) differs from the earlier HUI2 by modifying attributes and allowing more flexibility for capturing high levels of impairment. The authors compared HUI2 and HU13 scores of patients with Alzheimer's disease (AD) and caregivers, and contrasted results of a cost-effectiveness analysis of new drugs for AD using the two systems. Methods. In a cross-sectional study of 679 AD patient/caregiver pairs, stratified by patient's disease stage (questionable/mild/moderate/severe/profound/terminal) and setting (community/assisted living/nursing home), caregivers completed the combined HU12/HU13 questionnaire as proxy respondents for patients and for themselves. Results. Mean (SD) global utility scores for patients were lower on the HU13 (0.22[0.26]) than on the HU12 (0.53 [0.21]). Patient HU13 utility scores ranged from 0.47(0.24) for questionable AD to -0.23 (0.08) for terminal AD, compared with a range of 0.73 (0.15) to 0.14 (0.07) for the HU12. Among the 203 patients in the severe, profound, and terminal stages, 96 (48%) had negative global HU13 utility scores, while none had a negative HU12 score. The utility scores for caregivers were similar on the HUI3 (0.87 [0.14]) and HU12 (0.87 [0.11]). Cost-effectiveness analysis of a new medication to treat AD showed somewhat more favorable results using the HU13. Conclusions. The HU12 and HU13 discriminate well across AD stages. Compared with the HU12, the HUI3 yields lower global utility scores for patients with AD, and more scores for states judged worse than dead. The HUI3 may yield substantially different results from the HU12, particularly for persons who have serious cognitive impairments such as AD. Key words: Health Utility Index; Alzheimer's disease ; utility assessment. (Med Decis Making 2000;20:413-422)