We measured health utility (HU) in Thai HIV/AIDS patients using visual analog scale (VAS), EuroQOL (EQ-5D), and standard gamble (SG), determine the relationships between these HU measures and health-related quality of life (HRQOL) measures of HIV and patient characteristics, and assess the feasibility of the HU methods.
A sample of 120 HIV/AIDS patients was identified at Bamrasnaradura Infectious Disease Institute, Thailand, during September to December, 2004. Face-to-face interviews included VAS, SG, and EQ-5D, HRQOL assessment using the Thai abbreviated version of the World Health Organization quality of life (WHOQOL-BREF THAI) and HIV-related symptom instruments, questions about ease of understanding HU approaches and sociodemographic items. Data were analyzed with repeated-measures ANOVA, followed by Dunn–Bonferroni t-test, intraclass coefficients (ICC), Spearman's rank correlation, and multiple linear regressions.
The mean (95% confidence interval) HUs were as follows: VAS, 0.79 (0.76–0.82); EQ-5D, 0.80 (0.77–0.84); and SG, 0.65 (0.60–0.70). A significant difference in HU by method was found (P 0.001). Agreement by ICC was 0.71 for VAS versus EQ-5D, 0.41 for VAS versus SG, and 0.38 for EQ-5D and SG. The regression models showed that WHOQOL-BREF THAI, frequency of HIV symptoms, and patient characteristics could explain approximately 50% of the variation in the VAS and the EQ-5D and 20% in the SG. Among these three HU methods, the SG was the most difficult task.
VAS, EQ-5D and SG yielded different HUs for this sample. VAS and EQ-5D showed stronger construct validity with other health measures than SG. From a feasibility perspective, the SG was the least satisfactory of the three approaches.