How public and private health insurance coverage mitigates catastrophic health expenditures in Republic of Korea

Background The private health insurance (PHI) market in Republic of Korea has instituted indemnity insurance plans that provide partial reimbursements for some medical services or costs that are not covered by the National Health Insurance (NHI). To date, no study has estimated the extent to which PHI coverage lowers the economic burden of households' access to health care. The current study aims to evaluate the design of Korea's PHI system in terms of coverage using a catastrophic health expenditure (CHE) indicator and compare it with NHI. Methods This study determined the difference between the number of households that were subscribed to PHI and those that received reimbursements from PHI. Additionally, it compared the effects of reduced CHE by NHI benefits with PHI reimbursements. Furthermore, it compared PHI reimbursements based on income class. Finally, it analyzed the contribution of NHI and PHI to CHE reduction through a two-part model with hierarchical regression. Results The results indicated that of the 5644 households examined, 3769 subscribed to PHI, but only 246 households received reimbursements. Notably, NHI reduced CHE incidence by 15.17%, whereas PHI only reduced CHE by 1.22%. The NHI scheme indicated reduced inequality as it provided more benefits to the low-income class for their used medical services, whereas PHI paid more reimbursements to the high-income class. Accordingly, NHI coverage has protected households from CHE and improved equality to some extent; however, PHI coverage has had a relatively low effect on relieving CHE and has increased inequality. Conclusions The indemnity health insurance plans of PHI companies in Korea only cover partial medical costs or services, and so, most patients do not receive reimbursements. Thus, Korea's PHI system needs to improve to provide benefits to patients more generously and alleviate their financial burden. Keywords: Private health insurance; National health insurance, Insurance coverage, Republic of Korea, Catastrophic health expenditure