I really have to look into this:
[The Health Utility Index (HUI)]: The index [...] provides a description of an individual's overall functional health based on eight attributes - vision, hearing, speech, mobility (ability to get around), dexterity of hands and fingers, memory and thinking, emotion, and pain and discomfort. The HUI maps the responses into a scale ranging from negative to 1 (where one means perfect health and negative means worse than death).
With the exception of pain, how can any of the other attributes be 'worse than death'?
The excerpt is from 'Health Status, Health Care and Inequality: Canada vs. the U.S' (access for NBER subscribers).