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Abstract #46880 Published in IGR 13-3
Development of a multiattribute instrument for estimating utilities (preference weights) in people with glaucoma from the national eye institute visual functioning questionnaire (NEI-VFQ)
Kymes S; Peters CM; Beusterien K; Kotak S; Grinspan J; Stwalley D; Pleil AValue in Health 2011; 14: 56
OBJECTIVES: We used multi-attribute theory to develop a utility elicitation instrument for people with glaucoma based on the National Eye Institute-Visual Functioning Questionnaire (NEI-VFQ), a vision specific quality of life instrument frequently used in clinical trials. METHODS: NEI-VFQ responses for 1677 people enrolled in glaucoma prevention trials were analyzed to identify items responsive to differences in vision status. We then constructed a conjoint interview administered to 48 people with glaucoma and identified the 6 items of greatest importance to people with glaucoma. Using these results, we constructed a web-based interview using standard gamble (SG) and visual analog scales(VAS) administered to a community sample of 404 people. RESULTS: The five attributes most important to people with glaucoma (and responsive to change in disease status) were: ability to read,drivingatnight,abilitytoleavehome,needinghelpwithactivitiesandability to accomplish tasks. We added a sixth attribute, peripheral vision, even though it was not rated highly by the participants as this is an important function lost early in the disease process. Final utility estimates were made usinga method similar to that employed in the Health Utility Index. The results had excellent face validity and we note the range of utility loss from mild loss of function to severe difficulty: 1) Ability to read (0.011-0.039); 2) Driving at night (0.011-0.037); 3) Leaving home (0.014-0.056); 4) Needing help with activities (0.027-0.063); 5) Ability to accomplish tasks (0.016-0.046); and 6) Peripheral vision (0.008-0.032). CONCLUSIONS: We have developed an instrument that can be used to estimate the utility loss in people with glaucoma baseduponthe NEI-VFQ. Whenusedinclinicaltrials,theinstrumentwill provideanestimateof theutilitylossassociatedwiththeprogressionofglaucoma. Further work will be required to refine and validate these estimates.
S. Kymes. Washington University, School of Medicine, St. Louis, United States.
Classification:
14 Costing studies; pharmacoeconomics
