| To Register SMDM Homepage | |
|
|
|
||||
Purpose: The study explores the relationships between health state utility, measured using the Time-Tradeoff Method (TTO), and three non-preference based health measures: two general non-preference-based health measure, the SF-12 questionnaire and the GHQ instrument, and a disease-specific non-preference-based measure, the Visual Functioning Questionnaire-25 (VFQ-25), a questionnaire developed by the National Eye Institute (NEI) to measure visual health function.
Methods: Twenty-nine patients with Age-Related Macular Degeneration (AMD) were asked a series of questions to assess (1) the utility of their current vision by using the TTO method; (2) their general health using the SF-12 as well as the General Health Questionnaire (GHQ); and (3) current visual health using the VFQ-25. In addition, co-morbidities and their visual acuity were measured. Patients were stratified into two groups according to the degree of visual acuity loss in the better-seeing eye (group 1 (n=11): 20/20 –20/50, group 2 (n=18): worse than 20/50). Utility values obtained from the TTO were then correlated with scores from the above surveys including both the physical component scores (PCS-12) and mental component scores (MCS-12).
Results: The mean TTO for group 1 was .855 (σ = 0.191) and for group 2 was .608 (σ = .261). For Group 1, correlations between TTO, PCS-12, MCS-12, VFQ, Visual Acuity, co-morbidity, and GHQ, indicated that only VFQ was significantly correlated with TTO (p=0.002) and this relationship was very strong (r=0.828). This group also exhibited a moderate relationship with PCS-12 (p=0.098, r=.524) and MCS-12 (p=.098, r=0.524). Interestingly, these same results did not extend to Group 2. In fact, none of the above health measures was significantly correlated with TTO for this group.
Conclusions: The results suggest the VFQ-25, a non-preference-based disease-specific measure of visual functioning, was a better predictor of utility than general non-preference-based measures of health for patients recently diagnosed with AMD (group 1). For patients who have progressed further in the disease, no such consistent relationship was identified. It is expected that this finding is due to differences between more severely impaired patients in their ability to cope with their loss of vision. This indicates that disease-specific measures that capture how well the patient is coping with the disease in addition to their level of functioning may be better predictors of utility.
See more of Poster Session - Clinical Strategies; Judgment and Decison Making
See more of The 26th Annual Meeting of the Society for Medical Decision Making (October 17-20, 2004)