Purchase this article with an account.
J. Kowalski, J. Walt, B. Nafees, A. Rentz, D. Revicki, J. Brazier, R. Hays; Health State Utility Valuations Using Health States based on the Visual Function Questionnaire. Invest. Ophthalmol. Vis. Sci. 2009;50(13):3760.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The VFQ-25 is a 25-item targeted profile measure that assesses vision-related functioning in patients across a range of eye diseases. Condition-specific measures are viewed as more sensitive to treatment changes and more relevant to the impact on health-related quality of life (HRQL). Generic measures such as SF-36 (Ware et al, 1993) have been converted into preference measures (Brazier et al, 2002) and have led to descriptive systems to classify people into health states. Our aim was to elicit societal-based, country-specific utility values using the Visual Function Questionnaire-Utility Index (VFQ-UI), based on the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25).
Eight vision-related health states ranging from perfect vision to blindness were developed based on 6 items from the VFQ-25 identified using Rasch analysis. The health states described the impact that central vision loss (CVL) and peripheral vision loss (PVL) have on daily functioning. Members of the general public were recruited in four countries (Australia, Canada, UK and US) to participate in a time-trade off (TTO) interview. All participants rated all health states. Participants were asked to rank order the health states and complete the EQ-5D.
In total, 607 participants across UK, US, Australia and Canada, took part in the valuation survey. The mean EQ-5D VAS score for current health in each of the four countries ranged from 81.6 - 84.5. All rank order scores of the health states were in the expected order of ‘no difficulty’ to ‘dead’. Mean adjusted health state values produced a range from 0.343 (worst; ‘stopped doing work or hobbies’) to 0.956 (best: ‘no difficulty’). Preferences showed a decline in utility by health state severity. The UK had the widest range of health state valuations from 0.264 to 0.916 (worst to best health state). The Australian valuations ranged from 0.318 to 0.954. The US preferences ranged from 0.413 to 0.964. Canadian participants’ valuations offered the highest utility score for the best health state (0.989) and ranged from 0.989 to 0.377 for the worst health state.
This study reflects the value that society places on the avoidance of central and peripheral vision loss and associated HRQL, and demonstrates that the general population in 4 countries can differentiate among increasing severity levels of vision-loss health states derived from the VFQ-25.
This PDF is available to Subscribers Only