Advance Formation and Barriers to Implementing End-of-Life Preferences:Policy Challenges for South Korea’s Life-Sustaining Treatment System

Although South Korea’s Life-Sustaining Treatment Act institutionalized self-determination in end-of-life care, a substantial gap remains between stated preferences and care delivered near death. This study examines the pathway through which patient preferences are formed, documented, and translated into care. Using National Health Insurance claims for 2013–2023 (N ≈ 2.59 million decedents aged ≥ 65), we compare the pre-implementation (2013–2017) and post-implementation (2019–2023) periods, quantifying burdens through an LST Distress Index and associated expenditures. Claims are complemented by surveys of 500 older cancer patients, 1,000 bereaved family members, and a randomized experiment among 2,000 adults. Findings show that despite the Act, end-of-life LST exposure remains common, decisions are often delayed, and burdens concentrate in the final stage of life. This gap reflects frictions across linked stages: limited early conversations, unspecified or inaccessible documentation, uneven ethics committee access, uncertainty in determining the dying phase, and weak palliative care continuity. We propose policy interventions to strengthen the linkage between early preference formation and clinical execution, including integrating advance directives with physician-patient advance care planning, broadening participation, addressing institutional blind spots, and enhancing care continuity.