Health disparity and healthcare utilization inequity among older adults living in poverty in South Korea: a cross-sectional study

BACKGROUND: Korea has a two-tiered universal health security system: the wage-based National Health Insurance (NHI) program and government-subsidized Medical Aid (MA) program. Beneficiaries of the MA program belong to the lowest economic class. This study aims to investigate the association between economic status—defined as NHI or MA enrollment—and health disparity of older people aged ≥ 65 years in South Korea. METHODS: The claims records of 672,525 older age population from the 2017 Health Insurance Review and Assessment Service-Adult Patient Sample were used to estimate adjusted odds ratios (aORs) of MA vs. NHI beneficiaries for prevalence for common geriatric diseases. Logistic regression and negative binomial regression were used to investigate the association between economic status and prevalence or healthcare utilization for each disease. RESULTS: MA beneficiaries showed significantly higher prevalence than NHI beneficiaries for seven out of nine diseases (aORs ranging from 1.18 to 1.95). The discrepancy in the prevalence between the two groups was highest among those aged 65–69 years (aORs: 1.34–2.94), and diminished as they got older (aORs: 1.05–1.67). MA beneficiaries had significantly more outpatient visits to treat six diseases (aORs: 1.07–1.28), and more hospitalization to treat seven diseases (aORs:1.08–1.73) than NHI beneficiaries. CONCLUSION: The higher prevalence of common geriatric diseases among MA than NHI beneficiaries confirms unfavorable health disparity in the elderly living in extreme poverty. Similar or higher healthcare utilization in treating the same conditions among MA beneficiaries suggests a low possibility of inequity for access to healthcare resources covered by the universal health security system due to poor economic status. Greater excess use of inpatient than outpatient care by MA beneficiaries implies that the condition of poor older adults might be more severe when diagnosed with the same disease.