The impact of age-related macular degeneration on health status utility values.

Purpose: To estimate health status utility values in patients with age-related macular degeneration (ARMD) associated with visual impairments, by using preference-based measures of health.

Method: This was a cross-sectional study involving patients with unilateral or bilateral ARMD who attended a large teaching hospital. Patients underwent visual tests (near and distant visual acuity [VA] and contrast sensitivity [CS]) and completed health status questionnaires including the Index of Visual Function (VF)-14 and three preference-based measures (the Health Utilities Index Mark III [HUI-3], the EuroQoL Health Questionnaire [EQ-5D], and the Short Form 6D Health Status Questionnaire [SF-6D]) and the time tradeoff (TTO). The mean health status is presented for five groups, defined according to the VA in the better-seeing eye and for four CS groups.

Results: Two hundred nine patients were recruited with substantial loss of visual function as obtained by visual tests (mean decimal VA in the better-seeing eye: 0.2) and self-report (mean VF-14 score: 41.5). The mean (+/-SD) utilities were 0.34 +/- 0.28 for HUI-3, 0.66 +/- 0.14 for SF-6D, 0.72 +/- 0.22 for EQ-5D, and 0.64 +/- 0.31 for TTO. The HUI-3 had the highest correlation with VA and CS (0.40 and -0.34), followed by TTO (0.25 and -0.21). Across the VA and CS groups, only HUI3 and TTO had a significant linear trend (P < 0.05). In a regression model with CS and VA as explanatory variables, only the coefficient on CS was statistically significant.

Conclusions: ARMD is associated with a substantial impact on patients' health status, but this was not reflected in two of the generic preference-based measures used. The HUI-3 seems to be the instrument of choice for use in economic evaluations in which community data are needed. It may be more appropriate to base economic models on CS or some combination of CS and VA rather than on VA alone.