Decomposing income-related inequality in health-related quality of life in mainland China: a national cross-sectional study

Introduction Health equity is an important indicator measuring social development and solidarity. However, there is a paucity in nationwide studies into the inequity in health-related quality of life (HRQoL) in mainland China, in particular using the most recent data measuring HRQoL using the EuroQol 5-Dimension-5 Level (EQ-5D-5L). This study aimed to address the gap in the literature by estimating and decomposing income-related inequality of the utility index (UI) of EQ-5D-5L in mainland China. Methods Data were extracted from the Psychology and Behaviour Investigation of Chinese Residents (2022), including 19 738 respondents over the age of 18 years. HRQoL was assessed by the UI of the EQ-5D-5L. Concentration index (CI) was calculated to measure the degree of income-related inequality in the UI. The contributions of individual, behavioural and context characteristics to the CI were estimated using the Wagstaff decomposition method. Results The CI of the EQ-5D-5L UI reached 0.0103, indicating pro-rich inequality in HRQoL. Individual characteristics made the greatest contribution to the CI (57.68%), followed by context characteristics (0.60%) and health behaviours (-3.28%). The contribution of individual characteristics was mainly attributable to disparities in the enabling (26.86%) and need factors (23.86%), with the chronic conditions (15.76%), health literacy (15.56%) and average household income (15.24%) as the top three contributors. Educational level (-5.24%) was the top negative contributor, followed by commercial (-1.43%) and basic medical insurance (-0.56%). Higher inequality was found in the least developed rural (CI=0.0140) and western regions (CI=0.0134). Conclusion Pro-rich inequality in HRQoL is evident in mainland China. Targeted interventions need to prioritise measures that aim at reducing disparities in chronic conditions, health literacy and income.