Health Utility Measurement with Index Scores for People Living with HIV/AIDS Under Combined Antiretroviral Therapy: A Comparison of EQ-5D-5L and SF-6D
Authors: Wang Xiaowen , Luo Hongbing , Yao Enlong , Tang Renhai , Dong Wenbing , Liu Fuyong , Liang Jun , Xiao Minyang , Zhang Zuyang , Niu Jin , Song Lijun , Fu Liru , Li Xuehua , Qian Shicong , Guo Qing , Song zhizhong 
Published: February 2021

Abstract
BackgroundThe EQ-5D-5L and SF-6D are two widely used generic index score measures. We compared the discriminative validity, agreement and sensitivity of EQ-5D-5L and SF-6D utility scores in people living with HIV/AIDS (PLWHIV).MethodsWe conducted a cross-sectional survey among PLWHIV aged more than 18 years old in 9 municipalities in Yunnan Province, China. A convenience sample was enrolled. We administered the SF-12 and EQ-5D-5L to measure health-related quality of life (QALY). The utility index of the SF-6D was derived from the SF-12. The covariate data included demographic components, clinical components and social-psychology components. To evaluate the homogeneity of the EQ-5D-5L and SF-6D, intraclass correlation coefficients (ICCs), scatter plots and Bland-Altman plots were computed and drawn. To evaluate the capacity to discriminate between different categories of clinical components, social support and anxiety and depression status, mean and median scores were calculated and compared using one-way ANOVA and the Kruskal-Wallis test, respectively. The effect size was defined as the difference of each of the characteristics and was computed using Z/N. We also used receiver operating characteristic (ROC) curves to compare the discriminative properties and sensitivity of the econometric index.ResultsA total of 1,797 respondents, with a mean age of 45.6±11.7 years (range 18 to 80), was interviewed. The distribution of EQ-5D-5L scores skewed towards full health with a skewness of -3.316. The distribution of SF-6D scores was almost centered around its mean, and the skewness was 0.084. The effect size was smaller for the EQ-5D-5L than for the SF-6D across the social support, anxiety and depression subgroups. The overall correlation between EQ-5D-5L and SF-6D index scores was 0.46 (P<0.001). An ICC of 0.59 between the EQ-5D-5L and SF-6D meant a moderate correlation and indicated general agreement. The Bland-Altman plot displayed the same results as the scatter plot. The ROC curve showed that the AUC for the SF-6D was 0.776 (95% CI: 0.757, 0.796) and that for the EQ-5D-5L was 0.732 (95% CI: 0.712, 0.752) by the PCS-12, and it was 0.782 (95% CI: 0.763, 0.802) for the SF-6D and 0.690 (95% CI: 0.669, 0.711) for the EQ-5D-5L by the MCS-12.DiscussionOur study demonstrated evidence of the performance of EQ-5D-5L and SF-6D index scores to measure health utility in people living with HIV/AIDS. Both have shown discriminative capacity and validity in measuring health status. However, there were significant differences in their performance. Users need to pay more attention to the characteristics of the target population. HIV/AIDS has transformed from being a terminal illness to being a chronic disease. We preferred to apply the SF-6D to measure the health utility of PLWHIV during the cART period.Conclusion our study has demonstrated evidence for instrument choice and preference measurements in PLWHIV under cART. The differences between the measures could generate different health utilities for the same sample population, which is critical for cost-utility analyses that guide resource allocation and decision making.