Measuring quality of life in macular disease:what use are utilities?

Abstract

Background: Utility values are often used as measures of quality of life (QoL). This study compared the suitability of time trade-off (TTO) values with the MacDQoL. Participants completed the MacDQoL and vision and health-related TTO questions by telephone interview (n = 33) or self-completion (n = 100). 38 members, unable to read large print, completed a short telephone interview, including MacDQoL overview items and TTO questions.

Results: 100% completed the MacDQoL, 71% completed the vision-specific (health-specific = 75%) TTO question, of whom 38% (42%) said they would give up no years of life for restored vision (perfect health). Among those who would give up no years for restored vision (perfect health), proportions of blind, partially sighted and not registered people did not differ from the entire sample. Respondents considered factors other than their QoL when responding. The MacDQoL average weighted impact score was sensitive to vision status (r = 0.444, p < 0.01), as was the MD-specific QoL overview item (r = 0.426, p < 0.01), but the vision-specific TTO utility value was not.

Conclusion: The data support the validity of the MacDQoL but suggest that utility values provide no indication of QoL in people with MD.