DISCUSSION

In South Korea, 97.85% of suicide attempts are non-fatal (Suh, 2001). Previous research found that people with experiences of non-fatal suicide are at high risk of reattempt and are likely to sustain mild to severe injuries, incurring personal financial loss and socio-economic burden. In view of this, the State, which is the largest social unit, has an obligation to keep its citizens healthy (WHO, 1986). In the same vein, to provide basic data that can be managed by the central and regional authorities, this study sought to identify the socio-environmental factors that may affect the severity of the injury after a suicide attempt.

The results of this study revealed that the percentage of suicide attempts was significantly higher among females (55.2%), but the injury severity was significantly higher among males. These findings are consistent with those of previous studies on the older population (Jeon and Choi, 2012; Community Safety Promotion Research Institute and KCDC, 2009). Park and Bae (2006), who examined suicidal behavior, reported that males were more likely to engage in risky behavior than females, which may explain the higher severity of suicide injuries in males. In 2014, the year when the analysis of the present study was underway, males were at twice the risk of both severity of suicide injuries and suicide mortality compared to females (Statistics Korea, 2015).

As regards the mechanism of injury, the highest injury severity was associated with fire, followed by submersion, fall down, and self-poisoning. This differs from the finding of previous studies (Vyrostck et al., 2004; Jeong, 2017) that suffocation led to the highest number of deaths. This discrepancy could be ascribable to the different data used for analysis: previous studies used ER data whereas the present study used discharge data.

Kim et al. (2018) ranked unintentional injuries in the descending order of severity as follows: self-poisoning, road traffic injury, fire, and fall down (drowning was not included in the analysis of this study). Unlike the present study, in which injury severity was measured

in accordance with the ICISS based on the KNHDIIS data, the study by Kim et al. (2018) collected data from three sources, namely Statistics Korea Cause of Death, KNHDIIS, and Korean National Health and Nutrition Examination Survey, and combined the datasets and measured the severity of injury by calculating the annual inpatient/outpatient rate relative to the number of deaths, which was set at 1. This difference in approach led to the discrepancy in the definition of severity of injury. However, it could be confirmed that the mechanisms of injury differ between unintentional injury and suicide injury. This suggests that separate studies should be conducted with different approaches to deriving information necessary for developing intervention programs for unintentional injuries and suicide injuries.

Source of payment, which is used as a measure of the economic status of an individual, also showed statistical significance, wherein type-I and type-II Medicaid recipients showed the highest and lowest injury severity, respectively. In many previous studies that selected type of insurance as a variable (Na et al., 2009; Jeong, 2011; Kim et al., 2011), type-I and type-II Medicaid recipients were grouped together. Therefore, the statistical differences between type-I and type-II Medicaid recipients could not be reviewed. This suggests the need to differentiate between type-I and type-II Medicaid recipients in future studies of suicide.

In the correlation analysis, all variables with statistical significance showed weak correlations, presumably because the statistical indicators selected for the analysis were variables that reflect various social situations exposed to the influence of other factors, unlike variables collected under controlled conditions.

The variable with the highest explanatory power for correlation was A8 (Current status of urban population), which indicates the extent of urbanization. In this study, it was found that increase in the urbanization rate is correlated with decrease in the severity of injury.

This correlation also applies to mortality from suicide. In a study by Choi (2016) that analyzed 5-year datasets, annual suicide mortality rate was higher among rural population

than among urban population by approximately 11.57 persons per 100,000 population.

The variable with the next highest correlation coefficient was A51 (Share of social welfare budget in general accounting). Earlier studies (Park and Lee, 2014; Choi and Park, 2014) reported that suicide mortality rate and social welfare expenditure are negatively correlated. This finding was supported by the finding of the present study that ICISS and social welfare expenditure are positively correlated. In the present study, the closer the ICISS was to 1, the lower the severity of the injury, so this suggesting that social welfare expenditure is negatively correlated not only with the suicide mortality rate but also with the severity of injury.

With respect to the variables of local safety rating status, differences were observed in a study (Lee, 2016) when the place of injury occurrence was divided into home, the smallest socio-physical unit, and outside of home. However, in the present study, no correlation was observed between local safety rating status and the severity of suicide injuries.

As a result of regression analysis, A3 (Fishery Household Population), A59 (Consumer price change rate), and B16 (Local emergency medical institution) were identified as the factors affecting the severity of suicide injuries. After controlling for the human factors associated with the patients as well, ln (A26) (Mining) and B16 (Local emergency medical institution) were identified as the factors affecting the severity of suicide injuries.

Increase in fishery household population (A3) by 1,000 persons resulted in decrease in the severity of injury by 0.286. In contrast to the present study, in which data for farm and fishery household populations were collected separately, most previous studies grouped these populations together under farming and fishing villages or rural population, and some studies collected only data from farm households. Given the finding of the present study that the farm household population does not influence the severity of suicide injury, it is considered necessary to differentiate farm households from fishery households. In this context, while numerous studies of farming villages or farm household population have been conducted, hardly any studies of fishing villages or fishery household population

have been conducted.

Although there are no studies that can directly explain the effect of the variable fishery household population on the severity of suicide injury, a study by Yang and Cho (2014) noted that older adults living in urban households had a higher risk of suicide than did those living in fishery households. Similarly, Choi (2016) reported that older adults in regions with a low suicide mortality rate shared the common trait of continuing fishery activities, even after the age of 80 years, with no concept of retirement, and the aspects of strong solidarity and cohesion through frequent collaborative work in the coastal areas were emphasized. It is believed that groups that have strong bonds have a higher chance of discovering a suicide attempt and alarming the emergency medical system in a timely manner to reduce complications and sequelae, thus mitigating the severity of injury.

With each 1% increase in consumer price change rate (A59), injury severity decreased by 8.813. Consumer price change rate indicates the extent to which consumer price index (CPI) fluctuates (reference year: 2015). As a comprehensive measure of the price of goods or services, CPI serves as basic data for assessing inflation or as the basis for calculating wage increase (Statistics Korea, 2019). In the present study, CPI change rate was identified as an influential factor for the ICISS. However, CPI for living necessities (A60-A62), which are supplementary indicators of CPI that explains subjective consumer prices, was found to have no effect on it. This led us to investigate the wage status (Statistics Korea, 2014a) and to find that the wage increase rate had decreased for three consecutive years before it rose by 4.1% in 2014. Although it may be conjectured that wage increase is associated with the severity of suicide injury, the possible effect of wage increase rate on the severity of suicide injury could not be tested because the data used in the present study were single-year data. This topic requires further study.

B16 (Local emergency medical institution), which was identified as a variable that significantly affected the severity of suicide injuries in both human factors non-controlled and controlled models, represents the lowest-grade institution among emergency medical

institutions specified in Act on 119 Rescue and Emergency Medical Services. At each additional local emergency medical institution, the injury severity increased by 0.538 and 0.162 in the human factor non-controlled model and controlled models, respectively.

B-codes are socio-environmental variables applicable to the entire emergency medical system. Although regional emergency medical centers and specialized emergency medical centers, which are higher-grade institutions than local emergency medical institutions, were inputted as variables along with B16, they were found to have no effect on the severity of suicide injury. This may be attributable to the unique nature of local emergency medical institutions.

Unlike regional and specialized emergency medical centers that are designated based on geographical consideration or the number of residents in the given administrative district, local emergency medical institutions are designated though the process of the head of the institution submitting the necessary documents to the head of the competent local authority for review and approval. In particular, at the municipal level of si-gun-gu, the lower-tier administrative districts within a province jurisdiction, any hospital, including Korean traditional medicine hospitals and rehabilitation hospitals, with 30 or more beds are eligible to be designated as a local emergency medical institution. Under such circumstances, situations may arise wherein the immediate delivery of shared or multidisciplinary care or emergency surgery is not possible, often resulting in transfer to another hospital. According to earlier studies, the percentage of patients being transferred to another hospital due to lack of treatment capacity at the first hospital was over 70% (Lee et al., 2010; Jeong et al., 2011). In a more recent study (Choi et al., 2018), the patient transfer rate at local emergency medical institutions was reported to be over 37% during the three-year study period.

Furthermore, the mortality rate of transfer patients was about twice as high as non-transfer patients (Ahn et al., 2006).

Furthermore, facilities and staff of an average local emergency medical institution are not half the level of an average specialized emergency medical center, which is one grade

higher, and there is a considerable gap in the availability of test equipment or other equipment necessary for patient survival. Furthermore, only 76.9% of local emergency medical institutions satisfied all legal standards for infrastructure, equipment, and human resources in 2014, which was much lower than the percentage achieved by specialized emergency medical centers (94.4%) and regional emergency medical centers (97.5%). In particular, the compliance rate of legal requirements among local emergency medical institutions in provinces level locations was much lower than the compliance rate of those in metropolitan cities level locations (70.0% vs. 85.4%) (Ministry of Health and Welfare, 2016).

The “golden hour” (also known as golden time) for severely injured suicidal patients at the prehospital stage is one hour. Despite the need for professional care such as emergency surgery to be provided within this golden hour, local emergency medical institutions have less treatment capacity compared to regional and specialized emergency medical centers, which may have a negative impact on the severity of suicide injuries.

From the discussion above and the findings of previous studies, it may be inferred that there might exist differences in the severity of suicide injury between metropolitan cites level and provinces level locations.

Table 10 shows that the number of local emergency medical institutions is about 1.9 times higher in provinces (n=183) than in Metropolitan cities (n=95), and the population size to be covered by one institution is inversely proportional to the area to be covered by one institution. This could be attributable to the high population density in urban areas.

Choi and Lee (2013) reported that the probability of patient transfer is higher in areas with lower population density. In the data collected in the present study, the population density (A1) excluded from the regression analysis as a result of collinearity diagnosis for a relative risk regression analysis was found to be lower in provincial areas. Furthermore, in a study by Hwang et al. (2012), the total transport time from incident scene to the hospital was longer in areas with higher farming, fishery, and forestry populations. This points to the state of health inequalities due to regional differences in the availability of emergency

medical services or geographical characteristics. Moreover, in view of the findings of a study by Yoo (2008) that there is a difference in suicide mortality rate between rural and urban residents, it is necessary to conduct an in-depth study to examine whether there are differences in the factors influencing the severity of suicide injuries depending on regional characteristics and to operate emergency medical services based on the regional characteristics, reflecting the study results.

Table 10. An overview of the local emergency medical institutions (as of 2014)

No.¹⁾ Population per institution²⁾ (n)

Area per institution³⁾ (m²)

Metropolitan cities

Seoul 24 421,843 25,217,081

Busan 23 153,056 33,470,304

Daegu 8 312,075 110,442,514

Incheon 13 222,715 80,584,479

Gwangju 15 98,431 33,411,856

Daejeon 4 384,072 134,820,783

Ulsan 8 145,290 132,593,689

Provinces

Gyeonggi-do 31 397,564 328,151,143

Gangwon-do 19 81,106 885,556,713

Chungcheongbuk-do 15 105,170 493,808,766

Chungcheongnam-do 11 187,150 746,698,250

Jeollabuk-do 15 124,804 537,816,623

Jeollanam-do 35 54,376 351,686,625

Gyeongsangbuk-do 25 107,917 761,172,038

Gyeongsangnam-do 30 111,444 351,265,627

Jeju-do 2 301,261 924,522,755

Average (metropolitan cities) 13.6 245,629 78,648,672

Average (provinces) 20.3 162,002 597,853,171

1) Number of local emergency medical institutions (Source: National Emergency Medical Center, 2014)

2) Mid-year population of registered residents/number of the local emergency medical institutions (Source for the number of residents: Statistics Korea, 2014b)

3) Current administrative district size/ number of local emergency medical institutions Statistics Korea, 2014c)

There is also a need to reconsider transferring a severely injured suicidal patient requiring hospitalization to a local emergency medical institution. In the same vein, it is necessary that further studies establish methods to improve the current emergency medical system regarding local emergency medical institutions. The Korean Society of Emergency Medicine (2011) defined the emergency medical system as an organic collaboration system with all its components including the emergency response and care team, emergency medical information center, transport hospital, and hospital emergency team. Accordingly, it is necessary to investigate the effect of each of these components on the severity of suicide injury throughout the transport process to a local emergency medical institution, emergency medical care on arriving the hospital, and transfer to another hospital, as well as overall hospital system issues.

As for ln (A26) (Mining), which was identified as an influential factor together with B16 (Local emergency medical institution) in the human factor-controlled model, each additional worker in mining triggered an increase in the severity of injury by 2.340.

Mining has traditionally been an occupational group with the highest suicide risk, which remains unchanged even after controlling for socio-economic factors (Kposowa et al., 1999). A large number of studies have been conducted to investigate the factors associated with suicide among miners, such as depression (Considine et al., 2017), suicide attempt as well as suicidal impulse and ideation (Ahn et al., 2009; Baek et al., 2016), and suicide mortality rate (Portella, 2013; McPhedran, 2015). However, there are no studies on the severity of suicide injuries among miners, and it is hence impossible to verify the factors that can directly explain the results of the present study. Nevertheless, given the high incidence of respiratory diseases, such as pneumoconiosis (Ross, 2004) or ischemic heart disease (Landen, 2011), in the miner group compared with the non-mining group, it can be assumed that injury severity may have been higher due to such underlying diseases. Many researchers, including Kim et al. (2006), Lee et al. (2009), and Kim et al. (2010), have reported that patients with underlying diseases are at higher risk of high-severity injury

compared with patients without underlying diseases. On this note, residents in areas around mines have also been found to have poorer health than those living in other areas even after controlling for human factors, such as age, income, smoking, and obesity, irrespective of the fact that they do not work in the mining sector (M Hendryx, 2008). Such findings support the previously mentioned hypothesis that human and socio-environmental factors influence human health in a complex and interactive manner. To test this hypothesis, it is necessary to extend the results of this study by linking them to an information and knowledge base regarding personal medical conditions and other relevant factors.

In addition to an inherent limitation due to the use of raw data, the present study has the following limitations.

First, The statistic indicators of the Statistics Korea data was released at the national level without differentiating between Metropolitan city/Province and municipalities or internally collected but unreleased data, and the indicators released after 2014 had to be excluded from analysis even though they are indicators that may influence the severity of suicide.

Second, In the data collection phase, suicide injuries that patients concealed could not be selected as suicide data.

Third, Since data collection was limited to discharged patients, information about outpatients or those discharged from the ER without being hospitalized could not be included in analysis. Due to insufficient sample representativeness, the findings of this study cannot provide a comprehensive description of all suicide attempters. For cases involving suicide attempts, it is most appropriate to use data produced during outpatient visits or ER admission immediately after the suicide attempt. However, for the purpose of this study, KNHDIIS data were the only reliable data that provide residential and locational information about the patients, which are absolutely necessary for identifying the impact of socio-environmental factors on the severity of suicide injury. KNHDIIS data also enable

measuring the severity of injury, precluding the likelihood of false or distorted responses, and are the only data with nationwide generalizability. In order to overcome the limitations of this study and to promote research activities in this area, it is essential for institutions to collect patient data during outpatient visits and ER care to consider providing basic patient data including residential and locational information. To actively study this topic in the future, it would be necessary to examine institutions that collect data at outpatient and ER stages providing regional information of patients.

Based on the findings in the present study, the following proposals are made.

First, the present study set only statistical indicators as independent variables, thus precluding qualitative variables from analysis. However, in the research area involving injuries, both objective indicators and subjective perceptions must be considered (Cho and Park, 2008). According to the regression analysis, the impacts of variables not selected as input variables cannot be considered for analysis. It is therefore considered necessary to transform subjective perceptions to something analyzable, and consider them in future studies.

Second, if time-series analysis can be conducted by expanding the period covered by the collected data, more reliable results may be obtained. It should be noted, however, that a bias might occur if the continuity of publication of statistical indicators (independent variables) cannot be endured during time-series analysis or the definitions of variables are altered during the data collection period.

Third, most of the statistical indicators are published at the Metropolitan city/Province level. If all indicators are produced till the municipal district level, the data thus produced will be very useful for municipal-level local authorities in planning, implementing, and evaluating suicide prevention and intervention programs.

Fourth, if the methods used in the present study can be applied to other types of injuries

Fourth, if the methods used in the present study can be applied to other types of injuries