Advance Directives Split by Cognitive Status in Nationwide Study of Older Koreans

Only about one in ten older adults in South Korea has formally documented how they want to be treated at the end of life, and a sweeping new nationwide study suggests the reasons why depend strikingly on how well their brains are working. Researchers analyzing data from 9,951 community-dwelling older Koreans found that advance directive completion was associated with a different constellation of factors among those with cognitive impairment compared with those whose cognition remained intact. As South Korea has transitioned into a super-aged society, with roughly 10.5 million people aged 65 or older and an estimated 955,584 living with dementia, the question of who completes these legally recognized documents has become a pressing public health issue. The findings, published in Frontiers in Public Health, indicate that strategies to promote advance care planning may need to be tailored according to cognitive status rather than applied uniformly across the aging population.

The study drew on the 2023 wave of the National Survey of Older Koreans, a nationally representative survey administered every three years by the Korean Ministry of Health and Welfare. Trained interviewers conducted face-to-face, tablet-assisted personal interviews between September 4 and November 12, 2023, with participants identified through a two-stage stratified sampling design spanning all 17 Korean cities and provinces. Cognitive function was measured with the Korean version of the Mini-Mental State Examination for Dementia Screening, and participants scoring 1.5 standard deviations or more below the age- and education-adjusted normative mean were classified as cognitively impaired. By this criterion, 2,448 participants, or 24.6 percent of the sample, fell into the cognitive impairment group, while 7,503 retained normal cognition. The researchers then compared demographic profiles, health-related characteristics, emotional states, and attitudes toward death between completers and non-completers within each group using multivariable logistic regression.

The headline result is that completion rates were low in both cohorts: just 12.5 percent among older adults with cognitive impairment and 10.7 percent among those with normal cognition. Yet several factors were associated with completion regardless of cognitive status. Religious affiliation, poorer nutritional status, higher exercise frequency, participation in death preparation education, and higher awareness of the significance of dying well all raised the odds of having completed an advance directive in both groups. The dying-well awareness construct was derived from five survey items rating the perceived importance of end-of-life priorities, including preparing for one’s own dying process, dying free of pain, dying surrounded by family or close friends, not becoming a burden, and dying at home rather than in a hospital or care facility. Lower composite scores, reflecting greater perceived importance, were associated with higher odds of completion.

Within the cognitive impairment group, a distinct set of group-specific associations emerged. Completion was linked with younger age, with each additional year of age lowering the odds by roughly 3.5 percent, and with female sex, since the adjusted odds ratio for male sex was 0.399, meaning men were substantially less likely to have completed a directive. Higher educational attainment, greater prescription medication use, higher independence in activities of daily living, and higher depressive symptom scores were also associated with completion. Never having smoked, relative to current smoking, lowered the odds. The researchers note that the depression association, while statistically significant, was modest in magnitude, with each point on the 15-item Geriatric Depression Scale raising the odds by about 5.7 percent. Because the design was cross-sectional, the underlying mechanism linking depressive symptoms to completion cannot be established from these data.

The cognitively normal group showed a different pattern. Here, a higher number of chronic diseases and a history of falls within the past year were uniquely associated with advance directive completion, with falls raising the odds by 64.7 percent. Sex, by contrast, showed no significant association in this group, a sharp contrast with the cognitive impairment cohort where sex mattered considerably. The authors suggest, as a hypothesis not directly tested in the study, that for cognitively intact older adults, physical health events such as falls and accumulating chronic conditions may highlight bodily decline and prompt earlier engagement with end-of-life planning. If confirmed through longitudinal research, routine health encounters following a fall or a new diagnosis could represent natural opportunities to introduce advance directive discussions.

The single strongest correlate in both groups was prior participation in death preparation education, a structured program addressing end-of-life values and planning. Among cognitively normal participants, those who had taken such education were more than six times as likely to have completed an advance directive, with an adjusted odds ratio of 6.198. In the cognitive impairment group, the effect was roughly half as large, at 3.300, but still substantial. The authors frame this as evidence that end-of-life education is strongly associated with formal documentation regardless of cognitive function, while also noting that exposure remains rare. Nationally, the registration rate for advance directives among South Korean adults aged 19 or older stood at just 6.8 percent in 2025, and a reported 90.3 percent of individuals have never independently explored life-sustaining treatment systems or the completion process.

Perhaps the most striking discrepancy in the data is the gap between attitudes and action. In the cognitive impairment group, 82.2 percent disagreed with medical care for life prolongation, and in the normal cognition group, 85.3 percent did so. Negative attitudes toward non-beneficial life extension are therefore widespread, yet personal willingness does not automatically translate into formal documentation. The authors attribute this low completion rate to the fundamentally multi-layered nature of the determinants involved, which encompass sociodemographic characteristics, clinical conditions, health behaviors, psychological states, and structural accessibility. Similarly, while greater perceived importance of dying well was associated with completion, a reported 75.1 percent of community-dwelling older adults have never been introduced to the formal concept, meaning systematic exposure to these ideas remains low and the exact mechanism linking awareness to action warrants further empirical investigation.

The sex-specific finding adds a layer of complexity to an already mixed literature. Prior Korean studies have reported higher completion among both men and women depending on the sample, and a dyadic study of older American couples found that the association between cognitive function and completion differed according to spousal sex. The present study did not formally test for a statistical interaction between sex and cognitive status, because separate regression models were fitted for each group rather than a single pooled model with interaction terms. The authors therefore caution that their within-group findings do not statistically confirm between-group differences, and they call for future research designed to directly test sex-by-cognition interactions. Still, the observation that sex was significantly associated with completion only among cognitively impaired older adults suggests that men with cognitive impairment may warrant closer attention in advance care planning discussions.

The study carries notable strengths alongside clear boundaries. Its large, nationally representative sample of community-dwelling older Koreans allowed the factors associated with completion to be examined separately by cognitive status, which the authors describe as among the first such analyses using a nationwide dataset. However, the cross-sectional design precludes causal inference, and as a secondary data analysis the study was restricted to variables available in the original survey, notably lacking any measure of participants’ specific knowledge of advance directives, which may have produced residual confounding. Cognitive impairment was determined by a screening cut-off rather than a comprehensive clinical diagnostic assessment, so some misclassification is likely, and only community-dwelling adults able to provide self-reported data were included, meaning participants classified as impaired probably had relatively mild impairment. The researchers also used conventional unweighted logistic regression, which they argue is appropriate for estimating within-group associations but may affect standard error precision and population-level prevalence estimates.

The practical takeaway is that advance care planning promotion may work best when calibrated to cognitive status. For older adults with cognitive impairment, approaches that sensitively account for functional independence, psychosocial factors such as depressive symptoms, and sociodemographic characteristics including sex may deserve particular attention, especially since dementia’s progressive trajectory means planning should ideally occur before communication and decision-making capacities are lost. For cognitively intact individuals, educational approaches might leverage current health status and intact functional capacities, with chronic disease burden and fall history serving as potential triggers for conversation. Given that advance directive completion is associated with end-of-life care aligned with patient preferences, reduced use of non-beneficial life-sustaining treatments such as feeding tubes and mechanical ventilation, increased hospice utilization, and reduced emotional burden on family members during surrogate decision-making, closing the gap between intention and documentation could shape how millions age and die. The authors conclude that strategies to promote advance directive completion may need to be tailored according to cognitive status, while longitudinal research will be needed to confirm which approaches work best for the large majority of older adults still undocumented.

Subject of Research: Factors associated with advance directive completion among older adults with and without cognitive impairment: a nationwide cross-sectional study

Article Title: Factors associated with advance directive completion among older adults with and without cognitive impairment: a nationwide cross-sectional study

Article References: Choi, S., & Ko, H. (2026). Factors associated with advance directive completion among older adults with and without cognitive impairment: a nationwide cross-sectional study. Frontiers in Public Health, 14, Article 1957140. https://doi.org/10.3389/fpubh.2026.1957140

Image Credits: AI Generated

DOI: 10.3389/fpubh.2026.1957140

Keywords: Factors, associated, advance, directive, completion, older, adults, without, cognitive, impairment, nationwide, cross-sectional