Decomposing Income-Related Inequality in Health-Related Quality of Life in China: A National Cross-Sectional Study

Background: Health equity is an important indicator measuring social development and solidarity. However, there is a lack of studies into inequality in health-related quality of life (HRQoL) despite great progress in its measurements. This study aimed to address the gap in the literature by estimating and decomposing income-related inequality in HRQoL in China.Methods: Data were extracted from the Psychology and Behavior Investigation of Chinese Residents (PBICR, 2022), including 19,738 respondents over the age of 18 years. HRQoL was assessed by the EQ-5D-5L utility index (UI) and a visual analogue scale (VAS). Concentration index (CI) was calculated to measure the degree of income-related inequality in HRQoL. The contributions of individual, behavioral, and context characteristics to the CI were estimated using the Wagstaff decomposition method.Findings: There existed pro-rich inequality in HRQoL in China, with 0.0105 CI for the EQ-5D-5L UI and 0.0295 for VAS. Individual characteristics made the greatest contribution to the CI: 54.17% for UI and 33.37% for VAS, followed by health behaviors (0.05% for UI and 8.12% for VAS) and context characteristics (1.61% for UI and 1.76% for VAS). The contribution of individual characteristics was mainly attributable to disparities in the enabling (27.34% for UI and 28.86% for VAS) and needs factors (20.77% for UI and 6.60% for VAS), with health literacy (15.56% for UI and 27.04 % for VAS), chronic conditions (13.55% for UI and 3.88% for VAS), and average household income (12.58% for UI and 4.88% for VAS) as the top three contributors. Educational attainment, however, had a negative contribution (-5.02% for UI utility index and -2.30% for VAS) to the inequality. Higher inequality was found in the least developed rural (CI for UI 0.0086 and CI for VAS 0.0301) and western (CI for UI 0.0134 and CI for VAS 0.0301) regions.Interpretation: Pro-rich inequality in HRQoL is evident in China. Targeted interventions need to prioritize measures that aim at reducing disparities in health literacy, chronic conditions, and income.Funding: The study was funded by the National Natural Science Foundation of China (72174149), Humanity, and Social Science Foundation from the Ministry of Education of China (21YJAZH102), and the Key Research Institute Project of Humanity and Social Science of the Ministry of Education of China (1203-413100050).Declaration of Interest: We declare no competing interests.Ethical Approval: The survey was voluntary. Implied informed consent was obtained prior to each survey. This current study was approved by the Research Ethics Committee of the Health Culture Research Center of Shaanxi (JKWH-2022-02).