Content area
Abstract
Introduction. Different generic preference-based health-related quality of life (HRQOL) measures, including the SF-36v2, EQ-5D, HUI-3, and QWB-SA, can be used to assess several domains of health in a broad range of individuals. The SF-36v2 is one of the most commonly used measures, and has norm-based T-scores (mean=50, SD=10) which have not been updated since 1998. This dissertation evaluates how the scales of these generic HRQOL measures capture similar or unique constructs. Additionally, this dissertation establishes new U.S. norms for the SF-36v2. Methods The SF-36v2, EQ-5D, HUI-3, and QWB-SA were administered to 3,844 respondents (mean age=60; range 35 to 89; 57% female) in the National Health Measurement Study, a cross-sectional random-digit dial telephone survey of adults in U.S. households. Convergent and discriminant validity of the SF-36v2, EQ-5D, and HUI-3 were evaluated by multitrait-multimethod (MTMM) analysis of analogous attributes. Construct validity of the scales of all four HRQOL measures was also explored in the confirmatory factor analysis (CFA) of several 2-, 4-, and 5-factor models. In addition, weighted age- and gender-stratified SF-36v2 scale and component summary scores were computed. Results. MTMM analysis showed that the SF-36v2, EQ-5D, and HUI-3 similarly measure the constructs of physical functioning, mental health, and pain. Analysis of the best-fitting CFA model, a 5-factor model with physical functioning, self-care, pain, mental health, and social functioning factors, indicated that one or more scales from the SF-36v2, EQ-5D, HUI-3, and QWB-SA similarly measure physical functioning. CFA also supported the findings from MTMM analysis, and showed that the SF-36v2, EQ-5D, and HUI-3 provide similar information on pain and mental health. For the final analysis, almost all mean SF-36v2 scale and component summary scores were greater than 50.0. Higher SF-36v2 scores relative to the 1998 U.S. population were likely due to differences in the mode of administration. Discussion. In this dissertation, MTMM analysis and CFA show how the SF-36v2, EQ-5D, HUI-3, and QWB-SA may or may not similarly capture various health constructs. This dissertation also provides new U.S. norms for SF-36v2, which can be used as a reference to interpret scale and component summary scores for telephone-administered surveys.
