Projecting National Outpatient Health Expenditures Under Health Literacy Improvement Scenarios: A Simulation Study

Abstract

Background

South Korea’s Health Plan 2030 targets an increase in the proportion of adults with sufficient health literacy to 70% by 2030.

Methods

This scenario-based simulation study projected national outpatient healthcare expenditure from 2023 to 2030 using an ARIMA(1,1,1) model fitted to Korea National Health Accounts data (1970–2022). Two scenarios were compared: status quo (no change in health literacy distribution) and policy target (linear increase in sufficient health literacy from 49.3% in 2021 to 70% by 2030). An 8.6% expenditure differential between health literacy groups (95% CI: 1.3%–15.4%), estimated from the 2021 Korea Health Panel Survey, was applied with sensitivity analyses.

Results

National outpatient expenditure was projected to reach KRW 91.2 trillion by 2030 under the status quo, compared with KRW 89.5 trillion under the policy target scenario, representing savings of KRW 1.70 trillion (1.9%). Sensitivity analyses yielded projected savings of KRW 0.25–3.15 trillion.

Conclusion

These projections are conditional on modeling assumptions and do not imply causality, but suggest that achieving the national health literacy target may contribute to reducing outpatient expenditure and improving healthcare system efficiency.

Keywords

health literacy outpatient expenditure ARIMA model scenario-based simulation healthcare system efficiency

Introduction

Health literacy (HL) refers to the ability to access, understand, appraise, and use health information to make informed decisions about healthcare, disease prevention, and health promotion, thereby supporting quality of life throughout the life cycle.¹ The global significance of HL has been increasingly emphasized. In the 2016 Shanghai Declaration, the World Health Organization (WHO) identified HL as one of three key health promotion strategies.² More recently, the revised Health System Performance Assessment Framework, released by the Organization for Economic Co-operation and Development (OECD), highlighted the need for health systems to become more people-centered. In this context, the OECD underscored the importance of equipping populations with sufficient HL levels to support this shift.³

Consistent with these global trends, South Korea has designated HL enhancement as a national policy objective. Health Plan 2030, announced in 2023, identifies HL improvement as a core policy goal and sets the specific target of achieving a sufficient HL level among 70% of adults by 2030.⁴

Inadequate HL is significantly associated with increased mortality and morbidity rates, poor medication adherence, and low self-rated health status.^5-7 It is also associated with the increased use of unnecessary outpatient services, hospital admissions, and emergency department visits^.1,7-9 Furthermore, it has been linked to higher expenditures related to outpatient and inpatient care, pharmaceutical use, and emergency services.^9-13 Inadequate HL is associated with higher healthcare expenditure at the individual level, and avoidable healthcare costs attributable to inadequate HL are estimated to account for approximately 3 to 5% of total national health expenditure^10,13-15

However, the relationship between health literacy and healthcare utilization and expenditure should be interpreted with caution. The effect of improving HL on healthcare utilization and expenditure is not necessarily unidirectional. Improving HL may reduce unnecessary healthcare use while also increasing previously unmet necessary care, potentially increasing expenditure in the short term. In this sense, HL may operate less as a factor that uniformly reduces the volume of healthcare use than as a mechanism that facilitates a shift from inappropriate to appropriate use,^16-18 and its net effect may vary depending on the institutional context of the healthcare system.

South Korea reports the highest average number of outpatient visits among OECD countries, reaching three times the OECD average at 17.5 per capita in 2022.¹⁹ The South Korean healthcare delivery system is characterized by a privately dominated provider landscape, an absence of gatekeeping in primary care, and fee-for-service as the predominant reimbursement model. These structural features collectively facilitate the frequent and often provider-driven use of services, thereby contributing to higher outpatient spending and partially explaining the exceptionally high levels of outpatient expenditure. In this context, where optimizing outpatient utilization is itself an important policy concern, examining the potential implications of HL improvement for outpatient utilization and related expenditure as one policy scenario is of clear policy relevance.

Because the relationship between HL and healthcare expenditure is shaped by multiple mechanisms, its net population-level effect is difficult to estimate directly. In this regard, scenario-based simulation provides a useful approach for exploring possible outcomes under explicit assumptions. Given the policy target set in Health Plan 2030, such an analysis can provide a strategic baseline for assessing the potential fiscal implications of achieving the national HL target. The present study examines one policy-relevant scenario in which improved HL is assumed to influence outpatient utilization patterns, and evaluates its potential fiscal implications within the South Korean context.

This study aimed to project national outpatient healthcare expenditure under alternative health literacy scenarios and estimate the potential expenditure changes associated with achieving the national health literacy policy target.

Materials and Methods

Study Design

This study adopted a scenario-based simulation design to project changes in national outpatient healthcare expenditure in South Korea associated with improvements in population health literacy levels. The projection period spans 2023 to 2030. Two scenarios were developed and compared. The baseline projection assumes that the population’s health literacy level (status quo) remains unchanged through 2030. The policy target scenario assumes that 70% of the population will achieve a sufficient health literacy level by 2030, in alignment with the national health literacy policy goal(Health Plan 2030). Projected outpatient expenditure under each scenario was compared to estimate the potential change in national outpatient healthcare spending associated with health literacy improvement.

Data Sources

National Outpatient Expenditure

Outpatient expenditure data were obtained from the Korea National Health Accounts, specifically item H.C.3 (outpatient expenditure), covering the period from 1970 to 2022. The Korea National Health Accounts is an officially approved statistical system under Article 18 of the Statistics Act of Korea, developed in accordance with the System of Health Accounts 2011 (SHA 2011) guidelines jointly established by the OECD, WHO, and Eurostat, and has been widely adopted by numerous countries to produce standardized health expenditure statistics.²⁰ The dataset provides a comprehensive measure of total national outpatient healthcare expenditure, encompassing both public spending (e.g., national health insurance payments) and private spending (e.g., out-of-pocket expenses), including costs for non-covered services. Current price data were used without inflation adjustment, as the focus of this study is on estimating the relative difference in expenditure between scenarios rather than the absolute level of real healthcare costs.

Health Literacy

Health literacy data were obtained from the 2021 Korea Health Panel Survey (KHPS), a nationally representative, government-approved statistical dataset established under the Statistics Act of Korea to monitor healthcare utilization and expenditure among adults aged 19 years and older. As the health literacy survey was conducted only in the 2021 wave, this study was limited to 2021 data. Of the 11,914 eligible respondents, 3,284 individuals were excluded due to missing responses to one or more of the 16 health literacy items, yielding a final analytical sample of 8,630 participants. Health literacy was measured using the Korean version of the Health Literacy Survey European Questionnaire 16 (HLS-EU-Q16), the content validity of which was confirmed through expert review during the translation process and has been validated for use in the Korean population.²¹

Variables

Outcome Variable

The primary outcome of this study was the annual national outpatient healthcare expenditure (trillion KRW). In South Korea, where patients have direct and open access to outpatient services, outpatient expenditure most closely captures general healthcare utilization patterns at the population level. In contrast, inpatient care, emergency services, and health screening are largely necessity-driven and less subject to discretionary use.

Health Literacy

Health Literacy was assessed using the Korean version of the HLS-EU-Q16, a 16-item instrument developed to capture individuals’ health-related competencies across three domains: healthcare (7 items), disease prevention (5 items), and health promotion (4 items). Each item was rated on a 5-point scale, ranging from “very difficult” to “very easy,” with an additional “don’t know” option. For scoring purposes, responses indicating difficulty (“very difficult” or “fairly difficult”) were coded as 0, and responses indicating ease (“fairly easy” or “very easy”) were coded as 1. Respondents who did not answer one or more items were excluded from the analysis. This approach yielded a composite score ranging from 0 to 16.

It was categorized as inadequate (0–8), problematic (9–12), or sufficient (13–16). However, in the context of multivariate analysis, several studies have employed binary classification, distinguishing HL levels as either inadequate (scores of 12 or below) or sufficient (scores above 12). This study adopted the latter approach, categorizing respondents into sufficient and inadequate HL groups based on this threshold^.22-25

Statistical Analysis

Baseline Projection

National outpatient healthcare expenditure from 2023 to 2030 was projected using an ARIMA(p,d,q) model fitted to Korea National Health Accounts time series data spanning 1970 to 2022. The ARIMA model incorporates three components—autoregression (AR), differencing (I), and moving average (MA)—and is a well-established methodology for projecting healthcare expenditure trends in non-stationary time series data²⁶

Prior to model estimation, stationarity was assessed using the Augmented Dickey-Fuller (ADF) unit root test. A unit root was confirmed in the level series, and first-order differencing was applied (d=1). Following differencing, the unit root was rejected under the trend specification (Lag 0: p<0.0001; Lag 1: p=0.014). Candidate autoregressive (p) and moving average (q) orders were subsequently identified through inspection of the autocorrelation function (ACF) and partial autocorrelation function (PACF) plots, and a total of nine candidate models were estimated.

Optimal model selection was based on four criteria applied in combination: convergence under maximum likelihood estimation (MLE), the Akaike Information Criterion (AIC), statistical significance of all estimated parameters, and absence of residual autocorrelation as assessed by the Ljung-Box test. Among models satisfying convergence and white noise residual conditions, hold-out validation was performed using 1970–2019 as the training period and 2020–2022 as the validation period, with model performance evaluated by MAPE, MAE, and RMSE. The selected ARIMA(1,1,1) model is expressed as follows.

Δ y_{t} = c + ϕ_{1} Δ y_{t - 1} + ε_{t} - θ_{1} ε_{t - 1}

Δ y_{t} = y_{t} - y_{t - 1}

denotes the first-differenced value of national outpatient healthcare expenditure,

ϕ_{1}

and

θ_{1}

represent the autoregressive and moving average coefficients, respectively, and

ε_{t}

denotes the white noise error term. The estimated coefficients were

ϕ_{1}

= 0.985 and

θ_{1}

= 0.720. This model was selected as optimal among converged candidate models, yielding the lowest AIC (1599.432) and demonstrating strong predictive accuracy in hold-out validation (MAPE = 4.245%). Residual diagnostics confirmed the absence of autocorrelation, with Ljung-Box test results showing no significant residual autocorrelation at any lag (Lag 6: p = 0.200; Lag 12: p = 0.644; Lag 18: p = 0.454; Lag 24: p = 0.701). Normality of residuals was assessed using the Shapiro-Wilk test (W = 0.795, p < 0.001), with the violation of normality noted as a limitation of the model, as discussed in the Limitations section(Supplementary Table 1).

Policy Target Scenario

The policy target scenario was constructed based on the national health literacy policy goal of achieving 70% sufficient health literacy prevalence by 2030. Descriptive analysis of the 2021 KHPS data indicated that 49.3% of respondents were classified as having sufficient health literacy, and this proportion was assumed to increase linearly by 2.3 percentage points per year through 2030.

The expenditure differential between health literacy groups was estimated using a Generalized Linear Model (GLM) fitted to the 2021 KHPS data, with the natural logarithm of annual outpatient healthcare expenditure as the dependent variable, an identity link function, and heteroscedasticity-robust standard errors. Respondents with zero outpatient expenditure (n = 605, 7.0%) were excluded from the regression analysis, as log transformation is undefined for zero values, yielding a regression analytical sample of 8,025 participants. Covariates included sex, age, marital status, educational attainment, income level, private health insurance enrollment, and presence of chronic disease; full regression results are presented in Supplementary Table 2. Regression coefficients were exponentiated (exp[β]) for interpretation, where values below 1 indicate lower expenditure relative to the reference group and values above 1 indicate higher expenditure. The estimated exp(β) for the sufficient health literacy group was 0.914 (95% CI: 0.846–0.987), indicating that individuals with sufficient health literacy were associated with 8.6% lower outpatient expenditure (95% CI: 1.3%–15.4%) compared to those with inadequate health literacy.

National outpatient healthcare expenditure under the policy target scenario was derived by applying the following adjustment factor to the ARIMA(1,1,1) baseline projection:

E_{t}^{P S} = E_{t}^{S Q} \times \frac{1 - δ \times {H L}_{t}}{1 - δ \times {H L}_{2021}}

E_{t}^{S Q}

denotes the ARIMA-projected expenditure in year t, δ represents the estimated expenditure differential between health literacy groups,

{H L}_{t}

denotes the proportion of the population with sufficient health literacy in year t, and

{H L}_{2021}

= 0.493 is the baseline proportion in the reference year. This formula yields the relative change in outpatient expenditure attributable to the shift in sufficient health literacy prevalence from the baseline year to year t, and ensures that the two scenarios produce identical total outpatient expenditure in the reference year by construction.

To account for statistical uncertainty in the key parameter δ, sensitivity analyses were conducted using the 95% confidence interval bounds of the GLM estimate. Three scenarios were constructed applying δ = {0.013, 0.086, 0.154}, respectively, to characterize the range of projected savings under varying assumptions.

Results

Fitting the ARIMA(1,1,1) model to Korea National Health Accounts data spanning 1970 to 2022, national outpatient healthcare expenditure was projected to increase from KRW 64.2 trillion (95% PI: 62.1–66.4) in 2023 to KRW 91.2 trillion (95% PI: 79.0–103.4) in 2030, representing an average annual growth rate of 5.1% (Table 1). The width of the prediction interval widened progressively over the projection period, expanding from KRW 4.3 trillion in 2023 to KRW 24.4 trillion in 2030, reflecting increasing uncertainty in longer-term projections(Table 1, Figure 1).

Table 1.

National Outpatient Expenditure: Actual(1970-2022) and Forecast(2023-2030) With 95% Predicted Interval

Year	National outpatient expenditure (trillion KRW)	95% Prediction interval
2023	64.2	62.1–66.4
2024	68.2	64.7–71.7
2025	72.1	67.3–76.9
2026	76	69.8–82.1
2027	79.8	72.2–87.4
2028	83.6	74.6–92.7
2029	87.4	76.8–98.0
2030	91.2	79.0–103.4

Projections based on ARIMA(1,1,1) model fitted to Korea National Health Accounts data (1970–2022). 95% prediction interval derived from maximum likelihood estimation.

Figure 1.

National outpatient expenditure: Actual and forecast

Under the policy target scenario, national outpatient healthcare expenditure was projected at KRW 64.0 trillion in 2023 and KRW 89.5 trillion in 2030 under the base estimate (δ = 8.6%). Assuming that the proportion of the population with sufficient health literacy increases linearly from 49.3% in 2021 by 2.3 percentage points per year, reaching 70.0% by 2030, projected expenditure remained consistently below that of the status quo scenario (KRW 91.2 trillion in 2030). The gap between the two scenarios was negligible in the early projection years but widened progressively over time, reflecting the cumulative increase in the proportion of the population with sufficient health literacy (Table 2, Figure 2).

Table 2.

Policy Target Scenario: National Outpatient Expenditure (2023–2030)

Year	Sufficient HL (%)*	Status quo	Policy target (δ=1.3%)	Policy target (δ=8.6%)	Policy target (δ=15.4%)
2023	53.9	64.2	64.2	64	63.8
2024	56.2	68.2	68.1	67.8	67.4
2025	58.5	72.1	72	71.5	71
2026	60.8	76	75.9	75.2	74.5
2027	63.1	79.8	79.7	78.8	78
2028	65.4	83.6	83.5	82.4	81.4
2029	67.7	87.4	87.2	86	84.8
2030	70	91.2	91	89.5	88.1

HL = health literacy. Unit: Trillion KRW.

*Proportion of the population with sufficient health literacy is assumed to increase linearly from 49.3% in 2021 to 70.0% by 2030. δ = expenditure differential between sufficient and inadequate health literacy groups, derived from generalized linear model analysis (point estimate: 8.6%; 95% CI: 1.3%–15.4%).

Figure 2.

Projected national outpatient expenditure by Scenario(2023-2030)

Sensitivity analyses yielded projected expenditure of KRW 91.0 trillion in 2030 under the lower bound estimate (δ = 1.3%) and KRW 88.1 trillion under the upper bound estimate (δ = 15.4%), confirming the range of projections attributable to uncertainty in the key parameter. Across all three scenarios, a consistent pattern of lower projected expenditure associated with increasing sufficient health literacy prevalence was observed.

Comparing the status quo and policy target scenarios, projected savings associated with health literacy improvement were estimated at KRW 0.27 trillion (0.4%) in 2023 and KRW 1.70 trillion (1.9%) in 2030 under the base estimate (δ = 8.6%), indicating a progressive increase over the projection period (Table 3, Figure 3).

Table 3.

Projected Savings From Health Literacy Improvement(2023-2030)

Year	Status quo	Savings (δ=1.3%)	Savings (δ=8.6%)	Savings (δ=15.4%)
2023	64.2	0.04 (0.1%)	0.27 (0.4%)	0.49 (0.8%)
2024	68.2	0.06 (0.1%)	0.42 (0.6%)	0.78 (1.1%)
2025	72.1	0.09 (0.1%)	0.60 (0.8%)	1.11 (1.5%)
2026	76	0.11 (0.2%)	0.78 (1.0%)	1.46 (1.9%)
2027	79.8	0.14 (0.2%)	0.99 (1.2%)	1.84 (2.3%)
2028	83.6	0.18 (0.2%)	1.21 (1.4%)	2.24 (2.7%)
2029	87.4	0.21 (0.2%)	1.44 (1.7%)	2.68 (3.1%)
2030	91.2	0.25 (0.3%)	1.70 (1.9%)	3.15 (3.4%)

Figure 3.

Projected savings associated with health literacy improvement

Sensitivity analyses yielded projected savings of KRW 0.25 trillion (0.3%) in 2030 under the lower bound estimate (δ = 1.3%) and KRW 3.15 trillion (3.4%) under the upper bound estimate (δ = 15.4%), representing an overall range of KRW 0.25–3.15 trillion. Across all three scenarios, a consistent pattern of widening projected savings over time was observed, reflecting the cumulative increase in the proportion of the population with sufficient health literacy.

Discussion

This study projected national outpatient healthcare expenditure in South Korea under two health literacy scenarios using an ARIMA(1,1,1) model. Under the policy target scenario, outpatient expenditure in 2030 was estimated at KRW 89.5 trillion—KRW 1.70 trillion (1.9%) lower than the status quo projection of KRW 91.2 trillion, with projected savings ranging from KRW 0.25 to 3.15 trillion across sensitivity analyses. These projections are conditional on the modeling assumptions adopted and should not be interpreted as evidence of a causal relationship between health literacy improvement and expenditure reduction.

These findings suggest that achieving the national HL target may be associated with a reduction in outpatient healthcare expenditures. Prior international studies have estimated that 3–5% of total healthcare spending can be attributed to inefficient use resulting from inadequate HL.¹³ In the Korean context, even a 1–2% annual reduction in outpatient spending would mitigate rising healthcare costs and enhance the financial sustainability of the healthcare system.^13,14 It should be noted, however, that the projected savings in this study are limited to outpatient expenditure, and the association between HL and other components of healthcare costs—such as pharmaceutical expenses and inpatient costs—warrants further investigation.

The association between health literacy and healthcare utilization and expenditure may vary depending on a country’s healthcare system.²⁷ In Korea, the absence of a gatekeeping system requires patients to independently select healthcare providers and make health-related decisions, creating an institutional context in which supplier-induced demand is more likely to occur. The association observed in this study between higher HL and lower outpatient expenditures may be explained through several mechanisms. First, individuals with higher HL tend to critically evaluate information available in the healthcare market and selectively utilize services based on more accurate information^13,17.Second, they are more likely to actively use preventive services and receive appropriate care at early stages of illness, which may be associated with reductions in inefficient healthcare use such as emergency department visits and hospital readmissions.⁷ Third, they are less likely to engage in inappropriate healthcare utilization, such as consulting non-professional healthcare providers, which may reduce unnecessary medical expenditures.^28,29 These findings suggest that in healthcare systems without gatekeeping, health literacy may serve as a protective factor associated with more rational healthcare utilization among patients. It should be noted, however, that these mechanisms are interpretive in nature and based on associations observed in cross-sectional data; causal inference is not warranted.³⁰

It is also important to recognize that HL improvement does not necessarily result in a reduction in outpatient expenditure. Improved HL may be associated with increased use of preventive services or timely outpatient visits, which could raise short-term outpatient costs while contributing to better long-term health outcomes and cost savings.⁷ Moreover, improved HL may not only reduce direct medical costs but also lower indirect costs such as productivity loss and caregiver burden,³¹ effects that are not captured in the present projections and should be considered when evaluating the full economic implications of HL improvement.

To improve HL at the population level, a shift toward shared decision-making (SDM) in clinical practice is warranted. Healthcare settings are characterized by significant information asymmetry between providers and patients, and despite the emphasis on patient autonomy in Korea’s non-gatekeeping system, structural barriers often limit patients’ ability to have their preferences reflected in care decisions. SDM—a process in which clinicians and patients collaboratively make decisions based on clinical evidence and patient values—has been shown to strengthen HL and promote patient empowerment.³² Evidence suggests that SDM interventions may yield greater benefits among individuals with lower HL, offering potential for reducing health inequity. Achieving sustained impact will require not only clinical adoption but also institutional and financial support and proactive government engagement.

Although Korea’s current national health promotion plan aims to increase the share of adults with sufficient HL to 70%, policy discussions have largely focused on HL as a tool for health promotion rather than a lever for healthcare system efficiency. By contrast, several countries have adopted more strategic approaches, framing HL improvement as a cost-effective health system reform measure.^13,33 For example, the United States has recognized inadequate HL as a key driver of inefficiency and responded by introducing a national action plan to improve HL as part of broader efforts to reduce healthcare costs and improve outcomes.³³ Korea should adopt similar steps to integrate HL policy more fully into its broader health system and fiscal strategy.^34-36 When HL is addressed using a comprehensive, system-level approach, the country stands to gain not only improved health outcomes but also greater equity and more efficient use of limited healthcare resources. It should be noted, however, that this study did not estimate the cost of interventions required to achieve the 70% HL target; accordingly, the projected savings alone are insufficient to assess the cost-effectiveness of such policy efforts, and future research incorporating return-on-investment analyses is needed.^37,38

Limitations

This study had several limitations. First, the ARIMA model does not account for demographic changes or external shocks such as the COVID-19 pandemic or major policy reforms, and projections based solely on historical trends may underestimate future expenditure. Additionally, residual diagnostics revealed a violation of the normality assumption (Shapiro-Wilk W = 0.795, p < 0.001), which may affect the accuracy of prediction intervals.

Second, the assumed linear increase in sufficient health literacy from 2021 to 2030 is based on a single cross-sectional dataset, as no longitudinal data currently track population-level health literacy trends. The actual trajectory of change—whether logistic, stagnant, or otherwise—may differ, and as alternative trajectories of health literacy improvement were not explicitly modeled in this study, projected outcomes would vary accordingly. Moreover, projecting national-level impacts from a sample of 8,630 individuals involves inherent extrapolation uncertainty.

Third, the 8.6% expenditure differential between health literacy groups was derived from cross-sectional data and represents an association rather than a causal estimate. Reverse causality and residual confounding cannot be fully excluded, and as health literacy was measured using a self-reported instrument, measurement bias cannot be entirely ruled out. Additionally, respondents with zero outpatient expenditure (n = 605, 7.0% of the analytical sample) were excluded from the regression analysis due to the log transformation applied to the outcome variable, which may have introduced a degree of selection bias in the estimation of the expenditure differential. Validation through longitudinal studies is warranted.

Fourth, sufficient health literacy was defined using HLS-EU-Q16 scores from the 2021 Korea Health Panel. Although a national health literacy monitoring tool is currently under development based on the same instrument,³⁹ the threshold-based classification adopted in this study may not fully capture the complexity of health literacy as a construct.

Fifth, this study used aggregate national outpatient expenditure as the sole outcome, precluding disaggregation by cost component such as consultation fees, diagnostic testing, or pharmaceutical costs. The possibility of changes in accounting standards over the 1970–2022 data period cannot be entirely excluded, and aggregate data limit the direct isolation of individual-level health literacy effects. Furthermore, as intervention costs were not estimated, the projected savings alone are insufficient to assess cost-effectiveness; future research incorporating return-on-investment analyses is needed.

Finally, while sensitivity analyses using 95% confidence interval bounds (1.3%–15.4%) assessed the robustness of the key parameter estimate, replication using longitudinal data would further strengthen generalizability. As the findings are grounded in the structural characteristics of the Korean healthcare system—particularly the absence of primary care gatekeeping—direct generalization to countries with strong gatekeeping structures may not be appropriate.

Conclusions

This study employed a scenario-based simulation design with an ARIMA(1,1,1) time series model to project national outpatient healthcare expenditure in South Korea under two scenarios: maintaining the status quo and achieving the national health literacy policy target. The findings suggest that increasing the proportion of the population with sufficient health literacy to 70% by 2030 could be associated with a reduction in national outpatient expenditure of approximately KRW 1.70 trillion (1.9%) relative to the status quo scenario under the base estimate (δ = 8.6%), with projected savings ranging from KRW 0.25 trillion to KRW 3.15 trillion across sensitivity analyses. These results underscore the potential of health literacy not only as a health promotion tool but also as a strategic lever for improving healthcare system efficiency and financial sustainability. Given Korea’s rapidly aging population and structurally high outpatient utilization rate, investing in health literacy improvement could yield both individual and systemic benefits. Policymakers should view health literacy as a core element of health system reform and incorporate it into broader strategies for demand management, health equity, and long-term fiscal sustainability.

Supplemental Material

Supplemental Material - Projecting National Outpatient Health Expenditures Under Health Literacy Improvement Scenarios: A Simulation Study

Supplemental Material for Projecting National Outpatient Health Expenditures Under Health Literacy Improvement Scenarios: A Simulation Study by Seokjun Moon, Hansol Jang, Junghun Yoo, Dunsol Go and Hocheol Lee by INQUIRY: The Journal of Health Care Organization, Provision, and Financing.

Supplemental Material

Supplemental Material - Projecting National Outpatient Health Expenditures Under Health Literacy Improvement Scenarios: A Simulation Study

Supplemental Material

Supplemental Material - Projecting National Outpatient Health Expenditures Under Health Literacy Improvement Scenarios: A Simulation Study

Footnotes

ORCID iDs

Seokjun Moon

Hansol Jang

Junghun Yoo

Dunsol Go

Hocheol Lee

Ethical Considerations

This study used fully anonymized secondary data from the Korea Health Panel Survey (KHPS). The KHPS data collection was approved by the Institutional Review Board of the Korea Institute for Health and Social Affairs (KIHASA) (IRB No. 2022-017), and all personal identifiers were removed before the dataset was released for research use. The analyses in this manuscript were conducted as part of S.M.’s doctoral dissertation and received an exemption from further review from the Yonsei University Mirae Institutional Review Board (IRB No. 1041849-202409-SB-202-01). Because the dataset was fully anonymized and publicly accessible, the requirement for informed consent was waived. No identifiable information was available to the authors at any stage of the research.

Author Contributions

S.M. conceptualized and led the study, conducted the formal analysis, and drafted the manuscript. H.J., J.Y., D.G., and H.L. contributed to study design refinement, interpretation of the results, and critical revision of the manuscript. All authors reviewed and approved the final version of the manuscript.

Funding

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(RS-2024-00461755)

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Data Availability Statement

National Health Accounts (outpatient healthcare expenditure): Available from Statistics Korea at https://kosis.kr/index/index.do. Population projections: Available from Statistics Korea at https://kosis.kr/index/index.do. Korea Health Panel (KHP): Available from the Korea Health Panel Study () upon application and approval.

Supplemental Material

Supplemental material for this article is available online.

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