The concept of health literacy was originally introduced by Simonds, emphasizing its significance not only at the individual level but also within communal and governmental frameworks¹⁾. Defined by the World Health Organization as the capacity of individuals to comprehend, evaluate, and utilize health information effectively for the betterment of their well-being, the promotion of health literacy by governments has garnered increasing recognition²⁾. This recognition was further underscored by the

United Nations’ acknowledgment of health literacy as a pivotal determinant of health outcomes, as articulated in the Economic and Social Council Ministerial Declaration of 2009 in Geneva³⁾.

Under the auspices of the National Health Promotion Act, the 2030 Health Plan, comprising 28 initiatives across six domains, is progressing into its mid-stage within the Republic of Korea. Envisioning a society where universal lifelong health is realized, the plan’s initial focus lies on fostering health literacy among all citizens⁴⁾.

The burgeoning interest in health literacy has precipitated the development of various measurement tools⁵⁾. Findings from these assessments have consistently indicated lower levels of health literacy among older individuals and those with lower levels of education or socioeconomic status^6,7).

Previous researches have focused on prevention with health literacy⁸⁾, in addition, there were the results between high utilization with low level of health literacy^9,10). It is consistent in Republic of Korea¹¹⁾, no research has yet explored this relationship within the context of Korea’s dual medical system, which includes Korean Medicine.

To address these gaps, the 2021 Korean Health Panel Survey, for the first time, incorporated inquiries regarding health literacy, presenting an opportune moment to investigate disparities in health literacy across different medical institutions. Hence, this study endeavors to elucidate the variations in health literacy levels according to the type of primary medical institution visited, drawing insights from the aforementioned survey data. Furthermore, we conducted additional analyses that explore why health literacy levels may vary depending on the primary medical institution.

Table 1 presents the general characteristics of 5,361 participants. Among the predominant types of medical institutions, Western medicine clinics constituted the majority (61.11%, n=3,276), followed by Western medicine hospitals (35.80%, n=1,919), public health centers/clinics (1.81%, n=97), and KMC (1.29%, n=69). Gender distribution significantly differed across all institution types, with women comprising the largest proportion of visitors (p<.0001). Regarding age and education level (p=0.0002 and p<.0001, respectively), KMC visitors showed an even distribution, whereas older individuals and those with lower education levels were more prevalent among visitors to other institutions. In terms of mean household income, those who visit public health centers/clinics had the lowest level and those who KMC had the highest level (p<.0001); the gap was almost over twice. However, statistical significance was not noted primarily in the domains of marital status and occupation.

Table 2 delineates the findings of the survey based on HLS-EU-Q16. Health literacy scores significantly differed by the medical institution visited primarily (p=0.0003). The highest scores were observed among visitors to KMC (12.52±0.42), followed by Western medicine clinics (11.70±0.08), Western medicine hospitals (11.34±0.12), and public health centers/clinics (10.01±0.58). Notably, only two questions exhibited no significant differences: ‘Understanding the explanations of a doctor or pharmacist for how to take prescribed medications.’ and ‘Understanding why I need a medical check-up.’ For each question, participants primarily affiliated with KMC displayed the highest scores, followed by those attending Western medicine clinics, Western medicine hospitals, and public health centers/clinics, with the exception of one question: ‘Determining if information about health risks from the media is reliable.’ Whereas, the question of ‘Determining if information about health risks from the media is reliable.’ received the lowest rating, except for public health centers/clinics, where the question ‘Determining if you need to see another doctor after seeing one.’ was rated the lowest. The widest gap was observed in the question regarding ‘Determining how to prevent disease based on the information obtained from the media.’ while the narrowest disparity was noted in ‘Understanding the advice of family and friends about health.’

Table 3 illustrates the primary sources from which participants acquired medical information and their significant association (p=0.0063). Notably, the most common source across all participants found medical information on search engines, followed by television, medical staff, and social contacts (family/friends/coworkers/acquaintances). While individuals primarily attending Western medicine clinics and hospitals exhibited similar patterns to the overall sample, those attending public health centers/clinics obtained information predominantly from television, using search engines or YouTube, medical staff, or social contacts. Participants primarily associated with KMC favored using search engines, followed by medical staff, television or websites, YouTube, and social media networks affiliated with private or public health centers or clinics.

Notably, similar patterns were observed across all categories for the second priority source, with television, medical staff, and social contacts ranking highly. However, significant differences were noted in the preference for social contacts in public health centers/clinics and medical staff in KMC. For tertiary priorities, no specific favored source was predominant overall, followed by social contacts, television, and medical staff. Higher rates of choosing television in public health centers/clinics and social contacts in KMC were also noted, though without statistical significance. Table 4 elucidates the distribution of categorized HLS-EU-Q16 scores across the primary medical institutions utilized by participants, showing a significant association (p=0.0023). Notably, those primarily attending public health centers/clinics showed the lowest proportion of proficient health literacy levels compared to other groups. Conversely, the prevalence of deficiency in health literacy for those primarily visited KMC was lowest among individuals.

In the sub-group analyses, the significant difference in visitor frequency across primary medical institutions persisted only in the group under 65 years old (p=0.0429). This difference was not significant in the group aged 65 years and older (p=0.4520). Furthermore, no significant differences were observed when the analysis was stratified by chronic disease status.

This study identified several key findings regarding disparities in health literacy. Upon scrutinizing the disparities in health literacy based on the primary medical institution visited, notable differences emerged concerning sex, age, education level, and annual household income (p<.05 for all). A significant difference in total health literacy scores was observed, with the highest total score exhibited by KMC visitors and the lowest score found among those utilizing public health centers/clinics (p<.05). Regarding the individual assessment questions pertaining to health literacy, variations were evident across all inquiries except for two. Significantly, differences were found primarily in the realm of acquiring medical information, particularly concerning the first priority. Predominantly, participants relied on using search engines as their primary source of medical information, with the specific sequence varying according to their frequented medical institution. When categorizing HLS-EU-Q16 scores, it was observed that the higher health literacy groups was dominant, with the exception of those who frequently visited public health centers and clinics. In the result of sub-analysis, a significant difference based on the primary institution visited was observed only among the group under 65 years old.

Previous research based on the Korean Medical Panel Survey provided further context14. As the average health literacy score was determined to be 11.3, 29.3% were categorized as deficient, 20.1% as vigilant, and 50.6% exhibited a proper level of health literacy. Additionally, findings indicated that health literacy tended to be lower among women, rural residents, economically inactive individuals, older individuals, those with lower levels of education, and individuals from households with lower incomes. Regarding health information -seeking behavior, the most common approach was to utilize internet portals, followed by seeking information from television, healthcare professionals, and social contacts¹⁴⁾.

Compared to the previous study¹⁴⁾, distinctive characteristics of this study emerged based on the types of medical institutions participants primarily visited. Our findings align with the results of other studies; particularly noteworthy were findings indicating a higher prevalence of individuals with education levels below middle school and lower annual household incomes among those attending public health centers/clinics. Moreover, the married rate were lower in Western medicine clinics compared to others. In contrast to this finding, recent surveys on the utilization of Korean traditional medicine indicate high utilization rates among specific demographic groups such as women, older adults^15,16), and those with lower levels of education¹⁷⁾. This discrepancy, in contrast to the commonly reported high utilization of KMC by vulnerable populations (e.g., older adults, lower level of education), warrants careful discussion. While the Korean Health Panel utilizes a rigorous, nationally representative sampling design, the observed difference may be driven by the specific exclusion criteria applied in this analysis. Specifically, individuals lacking affiliation with major medical institutions were excluded from the analysis, potentially removing the most disconnected segment of the population. This process may introduce selection bias, resulting in a remaining sub-population that possessed sufficient health system literacy or proactive health-seeking behaviors. This secondary selection effect could therefore lead to an inflation of the measured health literacy score for KMC, reflecting a more informed and active sub-group rather than the general population of KMC.

Regarding health literacy itself, it is also consistent with the previous study in Australia¹⁸⁾, although there were differences in study type (panel survey vs. cross-sectional survey), measurement tool (HLS-EU-Q16 vs. Health Literacy Questionnaire), and participant type (community-based vs. inpatients). The authors found a tendency in public hospitals to be much less likely to have English-speaking staffs, patients with private health insurance, smokers, overweight individuals, those not participating in regular physical activities, and individuals prevalent in back pain, arthritis, and heart disease compared to private hospitals. Based on organizational characteristics such as environment, structure, values, practices, and workforce competencies, public hospitals may have a lower level of health literacy-responsive service delivery than private facilities. This aligns with our observation that PHC visitors, who often represent vulnerable populations, exhibited the lowest health literacy scores.

Beyond selection bias, other factors may also contribute to the observed health literacy differences. The first factor was suggested to be accessibility to public health centers/clinics. A previous study¹⁹⁾ concluded that public health hospitals were concentrated in urban areas, whereas public health clinics were dispersed across various cities and counties. When the factor of distance was weighted in calculating public health centers/clinics accessibility, the supply of medical services was found to be lower than the unadjusted rate (11.8 vs. 15.0 per 100,000 people). This rate was also lower for the elderly and Medicaid beneficiaries (11.4 and 12.2, respectively). This suggested a clear lack of public health centers/clinics accessibility. These groups are vulnerable not only in terms of access to medical services but also regarding health literacy¹⁴⁾.

The second factor indicated was literacy related to health insurance. According to Tipirneni et al. ²⁰⁾, health literacy for insurance may be associated with avoidance of medical service. Furthermore, the gap in health literacy could be a barrier for patients to access to make a choice regarding which medical institution they visit chiefly. In Republic of Korea, National Health Insurance (NHI) coverage decreased from 63.62% in 2000 to 25.25% in 2010 at Korean Medicine hospitals and from 30.33% in 2000 to 25.01% in 2010 at Korean Medicine clinics compared with about 20% in Western medicine clinics/hospitals for out-patients. Despite the improvement in the rate of coverage for Korean Medicine, it seemed to be expensive for out-patients in herb medicine and Tuina therapy among the types of treatment²¹⁾. Because the coverage rate varies for each treatment whether NHI covers it or not. The expansion of coverage in NHI narrowed the gap of the rate in out-of-pocket expenses between Western medicine and Korean Medicine and it is expected to eliminate barriers to access to choose what kind of medical institution they visit chiefly.

The third, existing tools for measuring health literacy were not suitable for traditional medicine. Some studies tried to evaluate health literacy in traditional medicine with them^22,23). It was revealed that factors including education, occupation, and income were associated with health literacy in traditional medicine between urban and rural areas²²⁾. Some disparities were drawn to different characteristics of population in each research. Even other research in Japan²⁴⁾, there was no association between acupuncture and health literacy. It would be possible that assessment tools have been generated for conventional medical practices, including dentistry and various diseases⁵⁾, efforts to evaluate health literacy pertaining to traditional medicine have been comparatively limited. Each country has own culture and medical system, especially dual medical system including traditional medicine. Health literacy also reflects them^22,25), therefore there is a pressing need for the development of tailored assessment models to gauge health literacy within the realm of traditional medicine, particularly within the context of the Republic of Korea. The same opinion was raised from the People’s Republic of China, which has a dual medical system²⁶⁾.

The focused attention on health literacy is warranted due to its direct and measurable impact on health outcomes. Individuals with low health literacy often encounter significant difficulty in identifying and selecting appropriate medical services for their specific needs. This difficulty subsequently leads to delays in accessing necessary care²⁷⁾ and, conversely, may result in the utilization of unnecessary health services²⁸⁾. Therefore, continuous monitoring of health literacy levels and active efforts to diminish these disparities are critical for improving public health and optimizing healthcare resource allocation.

Given the relevance of health literacy for traditional medicine, it is difficult to discuss it separately from the primary medical institutions that patients visit. This challenge arises because each country possesses a unique medical system that often integrates traditional medicine. Furthermore, the World Health Organization has recommended promoting primary health care in conjunction with traditional medicine²⁹⁾. In Republic of Korea, this integration is further solidified as the NHI system covers traditional medicine services. For these reasons, future health literacy research must be followed up with studies that include the context of traditional medicine.

Fourth, the tendency to visit a specific primary medical institution was found to be associated with differences in health literacy. Prior research has reported that women^30,31) and older adults³²⁾ were more likely to visit KMC, whereas women, older adults, and groups with lower income and lower educational attainment showed higher rates of visiting public health centers/clinics³³⁾. It is thus plausible that the type of primary medical institution visited contributes to wider disparities in health literacy. However, our additional analysis found that this difference remained significant even after adjusting for age and the presence of chronic diseases, suggesting that the type of visiting primary medical institution is a crucial factor influencing health literacy.

In addition to these reasons, those who belonged to low health literacy might have migrated from KMC to other institutions before conducting a survey. Since health literacy only gained recognition in the 1970s and has recently become established as an important determinant of health²⁾, it is difficult to accurately track patient shifts between different types of medical institutions specifically due to health literacy. However, these shifts might be inferred through other contributing factors. Rye reported that people who had preference with lower out-of-pocket and free to social stigma decided to visit public health centers/clinics³⁴⁾. Because of this preference, someone in lower health literacy might decide to visit public health centers or clinics. Furthermore, poor health outcome was led by low level of health literacy³⁵⁾. This relationship establishes a positive feedback loop: lower health literacy often leads to poorer health outcomes. For interrupting the feedback, it is needed to intervene by standing of community and government¹⁾.

In detail, two questions showed no significant difference based on the primarily visited medical institution, falling under the ‘comprehension’ category of the HLS-EU-Q16’s four categories. These findings suggest that individuals possess adequate knowledge of medication adherence and health check-ups regardless of their primary medical institution. This proficiency may be linked to their chosen sources of medical information; notably, three quarters of individuals in this study relied on mass media or online sources. Because these sources make people understand their condition and treatment as well as helping individuals consult medical staff confidently and adhere to directions or recommendations³⁶⁾. In contrast to this positive view, there is concern that an excessive provision of information could confuse individuals and lead to distrust in the information³⁷⁾. Therefore, it is crucial to ensure the accuracy of medical information disseminated through mass media or online platforms.

In aspect of origin for getting health information, they were reported that the less those used internet, the lower the health literacy was for pregnant women³⁸⁾ and that poorer e-health literacy was associated with not having access to a mobile device³⁹⁾. This was consistent with this study that the rate of using search engines was lowest in public health centers/hospitals was the source of medical information as 1st priority and the rate of deficiency in HLS-EU-Q16 was lowest too. As well, the rate of using search engines was highest in KMC was the source of medical information as 1st priority and the rate of deficiency in HLS-EU-Q16 was highest too. This finding could adjust countries using Internet and smartphone highly, however, it would be different in others using them less such as Africa under the average of 67.1%⁴⁰⁾. It is difficult to generalize because health literacy through digital media may deepen the gap, or it may reduce it, and further investigation is necessary in consideration of several factors in each region.

The higher total score of HLS-EU-Q16 observed among individuals primarily visiting KMC may primarily be attributed to the duration and satisfaction of consultations with doctors. Lee et al. determined that the average consultation time with outpatients in Western medicine clinics was 4.2±2.7 minutes and patients’ satisfaction was 6.3±4.1⁴¹⁾. In contrast, Bak et al. reported that Korean Medicine doctors spend an average of 14 minutes consulting with individuals, which is over three times longer than in Western medicine clinics⁴²⁾. This extended, patient-centered approach may contribute to greater patient satisfaction—with over three-quarters of KMC visitors expressing satisfaction (56.1%) or very high satisfaction (20.4%) in one survey⁴³⁾—thereby fostering improved health comprehension.

The sub-group analysis indicated that age serves as a moderating factor in the association between the primary medical institution visited and health literacy. The observed difference in health literacy based on the institution visited was significant only among the group under 65 years old (p=0.0429). This suggests that the younger group shows a stronger tendency to selectively choose their primary medical institution based on diverse socioeconomic factors, such as health status, income, and education level. Conversely, the institutional choices of the group aged 65 years and older are less influenced by these socioeconomic factors; instead, their choices may be driven by factors like geographical accessibility, healthcare subsidies, and chronic disease prevalence, which potentially dilutes the influence of socioeconomic variables on institutional choice⁴⁴⁾.

Through the Korea Health Panel Survey, this study found that health literacy was related to which medical institution participants usually visit as well as sex, age, education level, and income. Despite these findings, there were some limitations. First, while this study analyzed panel data, health literacy was measured only once; therefore, it did not capture the dynamic relationships typically afforded by panel data analysis. Second, in the data analysis, the analysis did not consider other potential confounding factors such as accessibility, health insurance literacy, or the use of alternative measurement tools. Despite these limitations, the established relationship between the type of primary medical institution visited and health literacy underscores its importance. Therefore, further research is necessary to fully explore these mechanisms and to develop targeted interventions aimed at improving health literacy across all primary visiting medical institutions.

This study explored the association between health literacy and the type of primary medical institution visited by participants, utilizing data from the Korea Health Panel Survey. In consequence, health literacy levels differed among groups visiting different types of medical institutions; more in women at all, more the older except KMC, lower educational level except KMC, and the lowest mean household income in public health centers/clinics. Health literacy was the lowest in public health centers/clinics and the highest in KMC. Especially the older and people with chronic diseases have more proportion of deficiency in health literacy. These differences warrant further longitudinal studies to clarify causal relationships, particularly when accounting for factors inherent to Korea’s dual healthcare system. We recommend the continuous monitoring of health literacy using panel data, the development of new measurement tools tailored for traditional medicine, and the establishment of targeted policies for improving health literacy across all healthcare settings.