Health-related inequalities in out-of-pocket expenditure under universal health coverage in Taiwan: A cross-sectional decomposition analysis.

Objectives: Studies have investigated income-related inequality in out-of-pocket expenditure (OOPE) on health care but less is known about health-related inequality of OOPE distribution. This study analysed the relationship between health-related inequality and OOPE and the factors contributing to OOPE inequality in Taiwan.

Methods: We developed a household OOPE questionnaire and conducted a nationally representative cross-sectional survey of households in Taiwan between January and August 2022, using two-stage probability proportional-to-size sampling based on a national address registry in Taiwan. We calculated a concentration index to determine OOPE inequality in health. We then identified factors contributing to OOPE inequality in health distribution by performing a decomposition analysis.

Results: A total of 657 people responded to the survey (81.4% response rate). The two largest categories of OOPE were spending on curative care and on medical goods and pharmaceuticals, with concentration indices of -0.265 (p < .001), -0.272 (p = .006) and -0.227 (p = .003), respectively, indicating that the OOPE burden fell disproportionately on people with poor health. Socioeconomic status explained significant proportions of inequality in total, curative and medical goods and pharmaceuticals OOPE. Utilisation of health care increased the OOPE burden among people with poor health while having private health insurance worked in the opposite direction.

Conclusion: In Taiwan, people in poor health faced a disproportionately high OOPE burden, indicating that the National Health Insurance scheme may not meet their needs for health care. There is a need for policies to take account of the different factors affecting health inequalities in OOPE in order to enhance equity in Taiwan's universal health system.