Factors influencing intentional self-harm in Chungcheongbuk Province relative to the Seoul region in the Republic of Korea: a retrospective study

Article information

Osong Public Health Res Perspect. 2024;15(6):497-507

Publication date (electronic) : 2024 November 27

doi : https://doi.org/10.24171/j.phrp.2024.0112

Hyun-Ju Lee

Department of Health Administration, Jungwon University, Goesan, Republic of Korea

Corresponding author: Hyun-Ju Lee Department of Health Administration, Jungwon University, 85 Munmu-ro, Goesan-eup, Goesan 28024, Republic of Korea E-mail: hyun525h@jwu.ac.kr

Received 2024 April 23; Revised 2024 October 7; Accepted 2024 October 23.

Abstract

Graphical abstract

Introduction

According to data from Statistics Korea, the suicide rate in the Republic of Korea has consistently been the highest among Organisation of Economic Co-operation and Development (OECD) and G20 member countries for the past several years, presenting a substantial social problem [1,2]. Previous studies have also indicated that the suicide rate in the Republic of Korea is more than twice the average of OECD countries, emphasizing the urgency of addressing suicide from a public health perspective [3]. As of April 2024, based on the latest available statistics, the suicide rate in the Republic of Korea in 2022 was 25.2 per 100,000 population, while the suicide rate in Chungcheongbuk Province (hereinafter, Chungbuk) was 29.0, exceeding the national average [4]. As illustrated in Table 1, the suicide rate in the Chungbuk region over 4-year period from 2018 to 2021 was consistently higher than the national average, ranking as the third highest after Chungcheongnam Province and Gangwon Province for 5 consecutive years. These statistics suggest that the elevated suicide rate in the Chungbuk region is not a transient phenomenon but rather an issue that has persisted over many years. Consequently, there is a pressing need to prioritize interest and research efforts targeting the Chungbuk region. Nonetheless, there is a scarcity of previous studies pertaining to suicide in the Chungbuk region.

Table 1.

Suicide rates in Chungbuk and nationwide in the Republic of Korea (2018–2022)

Research on suicide has encompassed a variety of demographic groups, including older adults, firefighters, nurses, and university students, across multiple disciplines such as social welfare, psychology, sociology, law, and health. Most of these studies have utilized cause of death statistics from Statistics Korea [5–14]. However, there has been a notable lack of research using data from the Korea Disease Control and Prevention Agency (KDCA) Discharge In-depth Injury Survey, especially in analyses focused on specific regions. Most existing research has concentrated on national trends, with regional analyses receiving minimal attention [3,15,16]. This lack of regional studies is largely due to the small number of suicide cases recorded in the Discharge In-depth Injury Survey data for specific areas such as Chungbuk, which typically sees about 30 suicide cases annually from a total of approximately 300,000 injury cases. Despite this limitation, the Discharge In-depth Injury Survey data is particularly valuable because it includes information on survivors, offering a more comprehensive understanding of suicide patterns than the cause of death statistics provided by Statistics Korea. This is especially important for areas like Chungbuk, which are characterized by higher suicide rates.

According to population statistics by age group and administrative district published by Statistics Korea, as of January 2024, the Republic of Korea’s total population was 51,313,912. Of this, Chungbuk accounted for 4,289,256 residents, making up 8.4% of the national population. Despite its relatively small size, Chungbuk is noteworthy for its consistently high suicide rates, which exceed the national average annually. This region, characterized by its aging demographic and numerous agricultural areas such as Goesan-gun and Boeun-gun, faces challenges associated with population decline. The age distribution in Chungbuk also deviates from the national average, with a lower proportion of individuals aged 20 to 39 years (23.1% compared to 24.8%) and a higher proportion of individuals aged ≥65 years (21.0% compared to 19.1%). In contrast, Seoul displays opposite characteristics, with a higher proportion of individuals aged 20 to 39 years and a lower proportion of individuals aged ≥65 years compared to the national average [4,17]. This study aimed to compare and analyze suicide characteristics between Chungbuk, an aging region, and Seoul, a younger region, to identify the unique characteristics and influencing factors of the Chungbuk region relative to Seoul. The findings from this study can inform the development of tailored mental health promotion interventions for suicide prevention in the Chungbuk region.

The term “intentional self-harm” is used to denote suicide in the Korean Standard Classification of Diseases (KCD) and the KDCA Discharge In-depth Injury Survey [18,19]. Specifically, the guidelines for using the raw data from the Discharge In-depth Injury Survey define “intentional self-harm” and “suicide” as interchangeable terms, clarifying that “intentional self-harm” encompasses suicidal intent among patients categorized as having a failed suicide attempt, a suicide reattempt, or suicidal intent. Although intentional self-harm can be categorized into suicide and non-suicidal self-harm without suicidal intent [20,21], distinguishing between these categories can be challenging, even after a thorough review of a patient's complete medical records. Consequently, this study also adopts the term “intentional self-harm” in reference to suicide, following the conventions of the KCD and the Discharge In-depth Injury Survey.

Materials and Methods

Explanatory Variables

The variables used in this study were categorized into 5 major groups based on the criteria outlined in the raw data usage guidelines for the Discharge In-depth Injury Survey (Table 2). These groups included demographic information such as sex and age. Individuals aged 50 to 64 years were classified as middle-aged and older, following the categorization by Park [22]. Admission information encompassed the source of payment, length of hospital stay, route of admission, number of beds, and hospital location. Due to insufficient data, sources of payment other than health insurance and medical aid were excluded from the analysis. The inclusion of the number of beds and hospital location as variables aimed to assess potential disparities in the availability and use of healthcare facilities between the Chungbuk region and Seoul. For hospital location, cases were classified based on whether the discharging hospital was within Chungbuk or outside it; the same classification approach was applied to cases from Seoul. Disease and treatment information covered the principal diagnosis, injury/poisoning classification, total number of diagnoses, and treatment outcome. The principal diagnosis was categorized according to the KCD criteria. The injury/poisoning classification combined the principal and other diagnoses, extracting codes related to injury or poisoning for precise classification per the KCD criteria. The total number of diagnoses was the sum of the principal and other diagnoses. Extrinsic information included the place of injury, activity at the time of injury, and the mechanism of injury. Information on self-harm poisoning and risk factors comprised the motive for suicide and the type of poison used. The dependent variables were segmented into 2 groups: the Chungbuk intentional self-harm group and the Seoul intentional self-harm group.

Table 2.

Summary of explanatory variables

Research Model

The research model was developed to explore differences in demographic, admission, disease and treatment, extrinsic, and poisoning & risk factors related to intentional self-harm between the Chungbuk and Seoul regions. It also aimed to identify the distinct influencing factors (Figure 1).

Figure 1.

Research model.

Results

Differences in the Demographic Characteristics of Individuals Who Engaged in Intentional Self-Harm between the Chungbuk and Seoul Regions

An investigation into the demographic characteristics of individuals who engaged in intentional self-harm across the Chungbuk and Seoul regions revealed statistically significant differences in all variables (Table 3). In both regions, higher rates of intentional self-harm were observed among women, with 62.9% in Seoul and 54.0% in Chungbuk (p<0.05). Regarding age distribution, in Seoul, the prevalence of intentional self-harm was highest in individuals under 50 years (51.9%), followed by those aged 50 to 64 years (29.9%), and the lowest in those aged 65 years and older (18.3%). Conversely, in the Chungbuk region, the highest prevalence was noted among middle-aged and older adults aged 50 to 64 years (43.5%), then those under 50 years (29.9%), and finally those aged 65 years and older (25.8%), reflecting regional differences (p<0.001).

Table 3.

Demographic characteristics of individuals who engaged in intentional self-harm in the Chungbuk and Seoul regions

Differences in the Admission Information of Individuals Who Engaged in Intentional Self-Harm between the Chungbuk and Seoul Regions

An analysis of the characteristics of admission information for cases of intentional self-harm in the Chungbuk and Seoul regions revealed significant differences in the number of beds and hospital location. However, there were no significant differences in payment method, length of hospital stay, or route of admission (Table 4). Regarding the number of beds, 80.0% of cases in the Seoul region involved hospitals with 500 or more beds, indicating a concentrated use of large hospitals. In contrast, only 56.6% of cases in the Chungbuk region involved hospitals with fewer than 500 beds, highlighting regional disparities (p<0.001). Concerning hospital location, 83.9% of patients who attempted intentional self-harm in the Seoul region were treated in hospitals within the same region, compared to 73.0% in the Chungbuk region (p<0.001).

Table 4.

Admission information of individuals who engaged in intentional self-harm in the Chungbuk and Seoul regions

Differences in Disease and Treatment Characteristics of Individuals Who Engaged in Intentional Self-Harm between the Chungbuk and Seoul Regions

An investigation into the disease and treatment characteristics of individuals who engaged in intentional self-harm in the Chungbuk and Seoul regions revealed statistically significant differences in the details of injury/poisoning classification and the total number of diagnoses. However, no differences were observed in the major categories of primary diagnoses or treatment outcomes between the 2 regions (Table 5). Regarding injury/poisoning classification, poisoning by drugs was the most common in both regions, though slightly more prevalent in Seoul (42.0%) than in Chungbuk (36.0%). Additionally, the incidence of wrist and hand injuries and head injuries was notably higher in Chungbuk (18.4% and 15.2%, respectively) than in Seoul (8.6% and 6.6%, respectively). There was also a significant difference in the average total number of diagnoses, with Seoul reporting more diagnoses (n=3.4) compared to Chungbuk (n=2.7) (p<0.001).

Table 5.

Disease and treatment information of individuals who engaged in intentional self-harm in the Chungbuk and Seoul regions

Differences in the Extrinsic Information of Cases of Intentional Self-Harm between the Chungbuk and Seoul Regions

An investigation into the characteristics of extrinsic information related to intentional self-harm in the Chungbuk and Seoul regions revealed statistically significant differences in the mechanisms of injury and the activities at the time of injury. However, there were no differences in the locations of these injuries (Table 6). The most common mechanisms of injury in the Seoul region were poisoning, cuts, and a combination of temperature-related injuries, drowning, and suffocation. In contrast, in the Chungbuk region, the most frequent mechanisms were poisoning, cuts, and falls. Notably, incidents of self-harm involving temperature-related injuries, drowning, or suffocation were significantly less common in Chungbuk (1.6%) compared to Seoul (7.8%) (p<0.01). Regarding the activities at the time of injury, the rate of self-harm during routine daily activities—excluding leisure activities, work, and travel to a destination—was significantly higher in the Chungbuk region (21.7%) than in the Seoul region (15.3%) (p<0.05).

Table 6.

Characteristics of extrinsic information of individuals who engaged in intentional self-harm in the Chungbuk and Seoul regions

Differences in the Characteristics of Self-Harm Poisoning and Risk Factors among Individuals Who Engaged in Intentional Self-Harm between the Chungbuk and Seoul Regions

An analysis of the characteristics of self-harm poisoning and risk factors for intentional self-harm between the Chungbuk and Seoul regions revealed a significant difference in the types of poison used, although the motives for suicide were similar (Table 7). In the Chungbuk region, the most common poison used for intentional self-harm was pesticide or herbicide, accounting for 38.4%, compared to only 7.3% in the Seoul region. Conversely, sleeping pills were the most commonly used substance for intentional self-harm in the Seoul region, comprising 50.9% of cases, whereas in the Chungbuk region, they accounted for only 32.8%, which is approximately 60% of the level in Seoul (p<0.001).

Table 7.

Characteristics of self-harm poisoning and risk factors of individuals who engaged in intentional self-harm in the Chungbuk and Seoul regions

Factors Influencing Intentional Self-Harm in the Chungbuk Region Relative to the Seoul Region

Binomial logistic regression analysis was conducted to explore the factors influencing intentional self-harm in the Chungbuk region compared to the Seoul region. To minimize bias in the analysis, variables that showed correlations, such as disease and treatment information and the mechanism of injury from extrinsic information, were excluded from the multivariate analysis despite their significance in the univariate analysis. As indicated in Table 8, the multivariate analysis identified several significant factors influencing intentional self-harm in the Chungbuk region relative to the Seoul region. These factors included sex, age, number of hospital beds, hospital location, activity at the time of injury, and type of poison, collectively explaining 39.4% of the variance (p<0.001). The analysis revealed that the likelihood of intentional self-harm was 1.232 times higher in females than in males (p<0.05); 2.327 times higher in middle-aged and older adults (ages 50 to 64) compared to those under 50 years old (p<0.01); 8.603 times higher in hospitals with <500 beds compared to those with ≥500 beds (p<0.001); 2.412 times higher for individuals using hospitals in different regions compared to those using hospitals in the same region (p<0.01); 2.217 times higher during daily activities compared to other specified activities (p<0.01); and 6.987 times higher for those who ingested pesticides or herbicides compared to other types of poison (p<0.001).

Table 8.

Factors influencing intentional self-harm in the Chungbuk region relative to the Seoul region

Discussion

This study utilized raw data from the Discharge In-depth Injury Survey, a nationwide survey that collects data from medical institutions by reviewing medical records. These records contain information about patients discharged after being admitted for injuries or poisoning. To ensure a robust dataset, the study included data spanning 9 years, from 2013 to 2021. From this dataset, patients who attempted intentional self-harm and resided in the Chungbuk or Seoul regions were identified and included in the analysis. The objective of this study was to explore regional differences in intentional self-harm between the Chungbuk and Seoul regions and to identify factors associated with intentional self-harm in Chungbuk compared to Seoul. This analysis aims to inform strategies for the prevention of intentional self-harm.

The univariate analysis revealed significant differences in intentional self-harm between Chungbuk and Seoul, based on 9 variables. These variables encompass demographic information (sex and age), admission details (number of beds and hospital location), disease and treatment specifics (injury/poisoning classification and total number of diagnoses), extrinsic factors (injury mechanism and activity at the time of injury), and information on self-harm poisoning and risk factors (type of poison).

The length of hospital stay is often influenced by the severity of the disease and other unrelated health issues, such as comorbidities. Therefore, it can serve as a metric for assessing the severity and number of additional diagnoses, with a higher number of diagnoses generally indicating greater severity [23]. This study found no significant difference in the length of hospital stay between the Chungbuk and Seoul regions, suggesting similar severity levels of intentional self-harm in both areas. However, the total number of diagnoses was significantly lower in the Chungbuk region compared to Seoul, which may be attributed to differences in the size of medical institutions. Larger institutions, which typically have more professionals capable of coding diagnosis names (Health Information Managers), tend to classify additional diagnoses more specifically. In this study, 80% of cases in the Seoul region involved medical institutions with ≥500 beds, compared to only 43.4% in the Chungbuk region. Consequently, the higher number of diagnoses in Seoul, despite similar severity levels, is believed to have been influenced by a bias related to the size of medical institutions. This is the reason the total number of diagnoses was excluded from the multivariate analysis. Further research is necessary to explore the classification of injury/poisoning and the total number of diagnoses among disease and treatment information according to the size of medical institutions for more accurate analysis. Regarding the mechanism of injury, poisoning was the most common cause, accounting for over 70% of cases in both regions. Other mechanisms, such as falls, drowning, and suffocation, were helpful in identifying characteristics, but the number of cases involving these mechanisms was too low to include in the multivariate analysis. Additionally, the variable classifying the type of poison used was highly correlated with the predominant response in the injury mechanism variable, leading to its exclusion from the multivariate analysis.

Based on the results of the multivariate analysis, several factors were identified as significant influencers of intentional self-harm in the Chungbuk region compared to the Seoul region. These factors include demographic information (sex and age), admission information (number of beds and hospital location), extrinsic information (activity at the time of injury), and information on self-harm poisoning and risk factors (type of poison). Intentional self-harm cases involving women, adults aged 50 to 64 years, hospitals with <500 beds, hospital located in other regions, injuries occurring during daily activity, and using pesticide or herbicide were higher in the Chungbuk region than in the Seoul region.

In the Chungbuk region, females accounted for 54.0% of intentional self-harm cases, aligning closely with the national rates of 55.5% in 2010 and 53.5% from 2016 to 2020, as reported in studies utilizing the Discharge In-depth Injury Survey [3,15]. However, this contrasts with the cause of death statistics from Statistics Korea, which show that the suicide rate per 100,000 population in Chungbuk was 38.3 among males and 19.4 among females [4]. This discrepancy arises because the Discharge In-depth Injury Survey includes both survivors and in-hospital deaths due to intentional self-harm, whereas the figures from Statistics Korea only account for deaths resulting from intentional self-harm.

With respect to age, middle-aged and older adults aged 50 to 64 years accounted for the highest percentage of intentional self-harm cases, with 43.5% in the Chungbuk region. This contrasts with the Seoul region, where adults under 50 years old represented the majority of cases. These findings diverge from those of a previous nationwide study, which aligned with the Seoul region’s results [15]. Given the limitations of attributing these outcomes solely to regional characteristics or the aging population in Chungbuk, further research is necessary. Follow-up studies, including qualitative research with focus group interviews, are essential to accurately determine the underlying causes. In contrast to the trends observed in Seoul and in nationwide data, where a higher rate of intentional self-harm was noted among individuals under 50 years of age, the Chungbuk region reported older age groups as more frequently involved in such incidents. Consequently, considering previous studies that have shown an increase in suicide rates with age, the risk of suicide in the Chungbuk region is expected to be higher. Therefore, Chungbuk should be recognized as a region in need of heightened attention and targeted prevention efforts [12].

Regarding demographic information, the incidence of intentional self-harm was 1.232 times higher among females than males, and 2.327 times higher among middle-aged and older adults, specifically those aged 50–64 years, compared to those under 50 years in the Chungbuk region relative to the Seoul region. Therefore, it is recommended that intentional self-harm prevention programs in the Chungbuk region specifically target and prioritize women, particularly those within the 50- to 64-year age bracket.

If proposed interventions for preventing intentional self-harm could be established based on demographic information such as sex and age, then admission data like the number of beds and hospital location clearly highlighted regional differences in healthcare utilization. The incidence of patients attempting intentional self-harm in medical institutions with <500 beds was 8.603 times higher in the Chungbuk region compared to the Seoul region. Thus, the number of beds emerged as the factor with the most significant regional disparity among all influential factors considered. The number of beds indicates the size of medical institutions, suggesting that patients in the Chungbuk region were less likely to use larger hospitals than those in the Seoul region. This finding presents a paradox from a medical resource standpoint, as it indicates a variation in hospital size preference despite no differences in the severity of cases between the 2 regions.

This stark disparity in healthcare utilization between the Chungbuk and Seoul regions is evident. Previous studies have shown that while 22.3% of medical institutions utilized by patients who attempted intentional self-harm were located in Gyeonggi Province and 13.9% in Seoul, only 3.1% were in the Chungbuk region [15]. As of 2024, the Chungbuk region lacks any medical institutions with 1,000 beds or more. The Chungbuk National University Hospital, the sole tertiary hospital in the area, has only 800 beds [24]. Consequently, if residents of the Chungbuk region seek medical care locally, they face significant limitations in accessing large medical institutions with 500 beds or more. Regarding hospital locations, a higher percentage of individuals used hospitals within their own region in Seoul compared to Chungbuk. Outside of Chungbuk, many hospitals are located in Daejeon or Cheonan in the Chungnam region. This means that patients in Chungbuk with severe conditions often need to seek treatment outside their region due to the scarcity of adequately equipped local hospitals. In contrast, the Seoul region has numerous hospitals capable of treating patients with severe conditions. Thus, the distribution of hospital locations serves as an indicator of the disparities in health resources and accessibility between these 2 regions.

Intentional self-harm during daily activities was found to be 2.217 times higher in the Chungbuk region compared to the Seoul region. Other activities, including sports, leisure, work, school, travel, and treatment, were also examined, but a detailed comparison was challenging due to an insufficient number of cases to categorize these activities further. Despite these limitations, the results of this study underscore the importance of prioritizing resources for managing daily activities in the development of mental health care plans for the Chungbuk region. However, the higher rate of self-harm during daily activities in Chungbuk cannot be solely attributed to its relatively older population compared to Seoul. Therefore, further research on this topic is necessary.

Previous studies have indicated that intentional self-harm by poisoning involves ingesting a poisonous substance and typically shows a lower rate of improvement compared to other self-harm methods [16]. Although this form of self-harm can be extremely painful and may result in lifelong sequelae, the incidence in the Chungbuk region was found to be 8.9% higher than in the Seoul region, highlighting a need for increased focus on this issue. Specifically, the rate of intentional self-harm by poisoning using pesticides or herbicides was 6.987 times higher in Chungbuk compared to Seoul. This disparity likely reflects the regional characteristics of Chungbuk, which has many agricultural areas where access to pesticides and herbicides is relatively easy. Consequently, there is a critical need for vigilant management to prevent easy access to these substances. Additionally, it is essential for both central and local governments to implement stringent controls on the sale and use of pesticides and herbicides, similar to the regulations applied to narcotics.

A previous study indicated that suicide rates due to financial issues tend to rise with increasing urbanization in areas where the deceased were employed [10]. Chungbuk features a mix of urban populations in cities like Cheongju, Jecheon, and Chungju, and rural populations in areas such as Gosan and Boeun. Consequently, it is crucial to tailor intentional self-harm prevention activities in Chungbuk to suit both rural and urban settings, rather than implementing a uniform program across the entire region.

Conclusion

The suicide rate in the Republic of Korea has consistently been the highest among all G20 and OECD member countries for several years. Notably, the suicide rate in the Chungbuk region is approximately 4 times higher than the national average, underscoring the need for focused attention on this area [1,2,4]. This study is significant as it explores the specific challenges faced by the Chungbuk region, whereas most research on intentional self-harm has typically examined national trends. This study is particularly important because it provides evidence to support the development of targeted intentional self-harm prevention programs and health promotion policies for the Chungbuk region, where regional-level studies have been scarce. Therefore, further research is necessary, employing various methods including comparing the severity of issues across regions based on the size of medical institutions, distinguishing between urban and rural areas within the Chungbuk region, and investigating why intentional self-harm is more prevalent during daily activities and among middle-aged and older adults aged 50 to 64 years in Chungbuk compared to Seoul. Additionally, it is recommended to increase both human and financial resources for mental health promotion programs aimed at suicide prevention, to regulate substances commonly used for addiction, and to implement education programs that transform awareness about mental health, tailored to specific ages and regions.

HIGHLIGHTS

Article information Continued