South Korea's healthcare expenditure: a comprehensive study of public and private spending across health conditions, demographics, and payer types (2011-2020).

Background: South Korea has witnessed a rapid increase in health expenditure, reaching USD 135 billion in 2021 and accounting for 9.3% of its GDP, surpassing the OECD average. Despite achieving universal health coverage, significant gaps remain in service coverage, leading to high out-of-pocket (OOP) expenses that expose households to financial burdens. Methods: This study examines healthcare spending in South Korea from 2011 to 2020 using national datasets, focusing on expenditures across two primary payer categories: public insurance and OOP payments. Data were stratified by health condition, age group, sex, type of care, and income level. A combination of the National Health Insurance (NHI) dataset and the Korea Health Panel Survey (KHPS) was used to estimate total health expenditures, with multiple imputation methods applied to address data gaps. Findings: Healthcare expenditure in South Korea rose significantly from $45.6 billion in 2011 to $76.9 billion in 2020, placing an increasing economic burden on the system. Public health insurance spending grew at an annual rate of 5.1%, while OOP expenses rose by 5.0% for covered services and 6.7% for uncovered services. Despite a shift toward greater public funding-with public expenditure comprising 64.4% of total spending in 2020-OOP payments still accounted for 35.6%, remaining above the OECD average. Individuals aged 60 and above contributed to 51.3% of total expenditures. Gender disparities emerged, especially in high-cost areas like obstetrics and gynecology, where women incurred higher OOP costs. Additionally, uncovered services experienced significant spending growth across all income levels, with major cost contributors including musculoskeletal disorders, urinary tract disorders, and chronic diseases such as hypertension and diabetes. Interpretation: This study highlights the need for targeted healthcare policies in South Korea to address rising costs and persistent inequalities. High OOP expenses disproportionately impact vulnerable groups, especially women and the elderly, while uncovered medical costs are growing across income levels, straining households. Conditions like musculoskeletal disorders, hypertension, and diabetes, along with gender-specific costs such as obstetric care, emphasize access inequities. Uncovered OOP expenses are rising faster than covered services, particularly among older adults. Addressing these issues requires policies to ease financial burdens and ensure equitable healthcare access. Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.