Exploration of health dimensions to be included in multi-attribute health-utility assessment.

OBJECTIVE: Measurement of health utility is important for quality improvement, but instruments vary in their content. Multi-attribute health utility measures typically assess a small number of health problems, e.g. the EuroQoL EQ-5D questionnaire explores five dimensions of health. We aimed to examine whether a small number of dimensions explains a sufficient amount of variance in self-perceived health, and what can be gained from adding additional dimensions.
DESIGN: Cross-sectional mail survey that explored health utility and self-perceived health.
SETTING: General resident population of French-speaking Switzerland. PARTICIPANTS: Non-institutionalized adults. MAIN OUTCOME MEASURES: EQ-5D (which measures mobility, self-care, usual activities, pain/discomfort, anxiety/depression and a visual analogue health scale between 0 and 100 (VAS)). A subsample rated five additional health dimensions (sleep, memory/concentration, energy/fatigue, sight/hearing, contacts with others).
RESULTS: In total, 349 adults returned the extended 10-item questionnaire. All added items were strongly and significantly associated with the VAS for perceived health. The proportion of variance explained (R(2)) in the VAS was 0.47 for the original EQ-5D items (adjusted for attenuation: 0.65), 0.47 for the new items (adjusted for attenuation: 0.65) and 0.56 for the 10 items together (adjusted for attenuation: 0.78). Forty-four percent of the respondents who had a perfect health utility on the EQ-5D reported at least one problem in the new health dimensions.
CONCLUSION: Self-perceived health among the general public is influenced by more health dimensions than are typically measured in a multi-attribute health-utility instrument.