Factors Affecting the Incidence of Hospitalized Pneumonia after Influenza Infection in Korea Using the National Health Insurance Research Database, 2014–2018: Focusing on the Effect of Antiviral Therapy in the 2017 Flu Season

Background@#This study aimed to investigate the effect of antiviral therapy following influenza outpatient episodes on the incidence of hospitalized pneumonia episodes, one of secondary complications of influenza. @*Methods@#In the National Health Insurance Research Database, data from July 2013 to June 2018 were used. All of the claim data with diagnoses of influenza and pneumonia were converted to episodes of care after applying 100 days of window period. With the 100-day episodes of care, the characteristics of influenza outpatient episodes and antiviral therapy for influenza, the incidence of hospitalized pneumonia episodes following influenza, and the effect of antiviral therapy for influenza on hospitalized pneumonia episodes were investigated. @*Results@#The crude incidence rate of hospitalized pneumonia after influenza infection was 0.57% in both males and females. Factors affecting hospitalized pneumonia included age, income level except self-employed highest (only in females), municipality, medical institution type, precedent chronic diseases except hepatitis (only in females) and antiviral therapy. In the 2017 flu season, the relative risk was 0.38 (95% confidence interval [CI], 0.29–0.50) in males aged 0–9 and 0.43 (95% CI, 0.32–0.57) in females aged 0–9 without chronic diseases, and it was 0.51 (95% CI, 0.42–0.61) in males aged 0–9 and 0.42 (95% CI, 0.35–0.50) in females aged 0–9 with one or more chronic diseases in the aspect of the effect of antiviral therapy on pneumonia. It suggests that antiviral therapy may decrease the incidence of pneumonia after influenza infection. @*Conclusion@#After outpatient episode incidence of influenza, antiviral treatment has been shown to reduce the incidence of hospitalized pneumonia, especially in infants and children, during pandemic season 2017. Antiviral therapy for influenza is recommended to minimize burden caused by influenza virus infection and to reduce pneumonia. In addition, medical costs of hospitalization may decrease by antiviral therapy, especially in infants and children.

Compliance of Antihypertensive Medication and Risk of Coronavirus Disease 2019: a Cohort Study Using Big Data from the Korean National Health Insurance Service

Background@#There is a controversy whether it is safe to continue renin-angiotensin system blockers in patients with coronavirus disease 2019 (COVID-19). We analyzed big data to investigate whether angiotensin-converting enzyme inhibitors and/or angiotensin II receptor blockers have any significant effect on the risk of COVID-19. Population-based cohort study was conducted based on the prescription data from nationwide health insurance records. @*Methods@#We investigated the 1,374,381 residents aged ≥ 40 years living in Daegu, the epicenter of the COVID-19 outbreak, between February and March 2020. Prescriptions of antihypertensive medication during the year before the outbreak were extracted from the National Health Insurance Service registry. Medications were categorized by types and stratified by the medication possession ratios (MPRs) of antihypertensive medications after controlling for the potential confounders. The risk of COVID-19 was estimated using a difference in difference analysis. @*Results@#Females, older individuals, low-income earners, and recently hospitalized patients had a higher risk of infection. Patients with higher MPRs of antihypertensive medications had a consistently lower risk of COVID-19 than those with lower MPRs of antihypertensive medications and non-users. Among patients who showed complete compliance, there was a significantly lower risk of COVID-19 for those prescribed angiotensin II receptor blockers (relative risk [RR], 0.751; 95% confidence interval [CI], 0.587–0.960) or calcium channel blockers (RR, 0.768; 95% CI, 0.601–0.980). @*Conclusion@#Renin-angiotensin system blockers or other antihypertensive medications do not increase the risk of COVID-19. Patients should not stop antihypertensive medications, including renin-angiotensin system blockers, because of concerns of COVID-19.

The Correlation of Comorbidities on the Mortality in Patients with COVID-19: an Observational Study Based on the Korean National Health Insurance Big Data

Background@#Mortality of coronavirus disease 2019 (COVID-19) is a major concern for quarantine departments in all countries. This is because the mortality of infectious diseases determines the basic policy stance of measures to prevent infectious diseases. Early screening of high-risk groups and taking action are the basics of disease management. This study examined the correlation of comorbidities on the mortality of patients with COVID-19. @*Methods@#We constructed epidemiologic characteristics and medical history database based on the Korean National Health Insurance Service Big Data and linked COVID-19 registry data of Korea Centers for Disease Control & Prevention (KCDC) for this emergent observational cohort study. A total of 9,148 patients with confirmed COVID-19 were included. Mortalities by sex, age, district, income level and all range of comorbidities classified by International Classification of Diseases-10 based 298 categories were estimated. @*Results@#There were 3,556 male confirmed cases, 67 deaths, and crude death rate (CDR) of 1.88%. There were 5,592 females, 63 deaths, and CDR of 1.13%. The most confirmed cases were 1,352 patients between the ages of 20 to 24, followed by 25 to 29. As a result of multivariate logistic regression analysis that adjusted epidemiologic factors to view the risk of death, the odds ratio of death would be hemorrhagic conditions and other diseases of blood and blood-forming organs 3.88-fold (95% confidence interval [CI], 1.52–9.88), heart failure 3.17-fold (95% CI, 1.88–5.34), renal failure 3.07-fold (95% CI, 1.43–6.61), prostate malignant neoplasm 2.88-fold (95% CI, 1.01–8.22), acute myocardial infarction 2.38-fold (95% CI, 1.03–5.49), diabetes was 1.82-fold (95% CI, 1.25–2.67), and other ischemic heart disease 1.71-fold (95% CI, 1.09–2.66). @*Conclusion@#We hope that this study could provide information on high risk groups for preemptive interventions. In the future, if a vaccine for COVID-19 is developed, it is expected that this study will be the basic data for recommending immunization by selecting those with chronic disease that had high risk of death, as recommended target diseases for vaccination.

Age-Period-Cohort Analysis of Influenza in Koreans: the National Health Insurance Research Database, 2009–2018

Background@#This study aimed to identify the incidence rate of episodes diagnosed with influenza and the effects of age-period-cohort (APC) in Koreans. @*Methods@#The 2009–2018 National Health Insurance Research Database was used for analysis. All time-related claims connected relatively short window period in 100 days. The case definition was defined by all codes diagnosed with J09, J10, and J11. Calculation of the incidence rate and APC analysis adjusted income levels by insurance type, metropolitan city was performed to identify the characteristics of episodes diagnosed with influenza. @*Results@#Incidence rate by age and cohort gradually increased since 2014. The incidence rate of males aged 0–4 years was 171.02 and that of females was 173.31 in 2015–2016 season. In males, 29.19 in 1963 cohort and 243.79 in 2013 cohort were confirmed as high incidence rates in 2017–2018 season. In the females, a high incidence was confirmed in 1953–1967 cohort and 1978–1987 cohort, and the incidence was 251.38 in 2013–2017 cohort. APC effects showed a high relative risk in the infants, the pandemic influenza season in 2010 (1/7/2009 to 30/6/2010) and the adults of 1978–1987 cohort. @*Conclusion@#Since 2014, influenza outbreaks have been increasing every year. The start year of free vaccination decreased the incidence in infants and adults over 65 years of age but the incidence increased from the following year. Because influenza can be primarily prevented by vaccination, reinforcement of vaccination in infants may reduce the disease burden in their parents, and also the risk of infection caused by family transmission. A new vaccination strategy is needed to reduce the incidence and burden of diseases caused by influenza infection.

The coverage rates for influenza vaccination and related factors in Korean adults aged 50 and older with chronic disease: based on 2016 Community Health Survey data / 한국역학회지

OBJECTIVES: This study aims to identify the coverage rates for influenza vaccination and related factors depending on chronic disease in Korean adults aged 50 and older.METHODS: The 2016 Korea Community Health Survey was used for analysis. Chi-square test was performed to investigate the coverage rates for influenza vaccination depending on chronic disease, and a multiple logistic regression analysis was used to identify the factors associated with influenza vaccination, by chronic disease.RESULTS: In men with ≥1 chronic disease, 39.8% of 50-64 years of age, and 86.8% of elderly (over 65 years of age) received influenza vaccination. In women with ≥1 chronic disease, 58.7% of 50-64 years of age, and 89.9% of elderly (over 65 years of age) received influenza vaccination (p<0.001). The chronic diseases associated with influenza vaccination were hypertension (odds ratio [OR], 1.27; 95% confidence interval [CI], 1.19 to 1.37), diabetes (OR, 1.41; 95% CI, 1.28 to 1.55) in men aged 50-64, hypertension (OR, 1.34; 95% CI, 1.20 to 1.49), diabetes (OR, 1.17; 95% CI, 1.02 to 1.33), chronic cardiovascular disease (OR, 1.31; 95% CI, 1.07 to 1.60) in elderly (over 65 years of age). In women aged 50-64, hypertension (OR, 1.39; 95% CI, 1.30 to 1.49), diabetes (OR, 1.51; 95% CI, 1.35 to 1.68), chronic cardiovascular disease (OR, 1.31; 95% CI, 1.05 to 1.64), and hypertension (OR, 1.55; 95% CI, 1.40 to 1.71), diabetes (OR, 1.27; 95% CI, 1.12 to 1.43) in elderly (over 65 years of age).CONCLUSIONS: Populations in aged 50-64 are recommendation subject for vaccination or classified as high-risk group in case with chronic disease. Though subject over 60 years old is age close to the elderly, the coverage rates for vaccination was low. It is necessary to devise strategies to raise the coverage rates for vaccination.

The coverage rates for influenza vaccination and related factors in Korean adults aged 50 and older with chronic disease: based on 2016 Community Health Survey data / 한국역학회지

OBJECTIVES: This study aims to identify the coverage rates for influenza vaccination and related factors depending on chronic disease in Korean adults aged 50 and older. METHODS: The 2016 Korea Community Health Survey was used for analysis. Chi-square test was performed to investigate the coverage rates for influenza vaccination depending on chronic disease, and a multiple logistic regression analysis was used to identify the factors associated with influenza vaccination, by chronic disease. RESULTS: In men with ≥1 chronic disease, 39.8% of 50-64 years of age, and 86.8% of elderly (over 65 years of age) received influenza vaccination. In women with ≥1 chronic disease, 58.7% of 50-64 years of age, and 89.9% of elderly (over 65 years of age) received influenza vaccination (p<0.001). The chronic diseases associated with influenza vaccination were hypertension (odds ratio [OR], 1.27; 95% confidence interval [CI], 1.19 to 1.37), diabetes (OR, 1.41; 95% CI, 1.28 to 1.55) in men aged 50-64, hypertension (OR, 1.34; 95% CI, 1.20 to 1.49), diabetes (OR, 1.17; 95% CI, 1.02 to 1.33), chronic cardiovascular disease (OR, 1.31; 95% CI, 1.07 to 1.60) in elderly (over 65 years of age). In women aged 50-64, hypertension (OR, 1.39; 95% CI, 1.30 to 1.49), diabetes (OR, 1.51; 95% CI, 1.35 to 1.68), chronic cardiovascular disease (OR, 1.31; 95% CI, 1.05 to 1.64), and hypertension (OR, 1.55; 95% CI, 1.40 to 1.71), diabetes (OR, 1.27; 95% CI, 1.12 to 1.43) in elderly (over 65 years of age). CONCLUSIONS: Populations in aged 50-64 are recommendation subject for vaccination or classified as high-risk group in case with chronic disease. Though subject over 60 years old is age close to the elderly, the coverage rates for vaccination was low. It is necessary to devise strategies to raise the coverage rates for vaccination.

The coverage rates for influenza vaccination and related factors in Korean adults aged 50 and older with chronic disease: based on 2016 Community Health Survey data / 한국역학회지

OBJECTIVES@#This study aims to identify the coverage rates for influenza vaccination and related factors depending on chronic disease in Korean adults aged 50 and older.@*METHODS@#The 2016 Korea Community Health Survey was used for analysis. Chi-square test was performed to investigate the coverage rates for influenza vaccination depending on chronic disease, and a multiple logistic regression analysis was used to identify the factors associated with influenza vaccination, by chronic disease.@*RESULTS@#In men with ≥1 chronic disease, 39.8% of 50-64 years of age, and 86.8% of elderly (over 65 years of age) received influenza vaccination. In women with ≥1 chronic disease, 58.7% of 50-64 years of age, and 89.9% of elderly (over 65 years of age) received influenza vaccination (p<0.001). The chronic diseases associated with influenza vaccination were hypertension (odds ratio [OR], 1.27; 95% confidence interval [CI], 1.19 to 1.37), diabetes (OR, 1.41; 95% CI, 1.28 to 1.55) in men aged 50-64, hypertension (OR, 1.34; 95% CI, 1.20 to 1.49), diabetes (OR, 1.17; 95% CI, 1.02 to 1.33), chronic cardiovascular disease (OR, 1.31; 95% CI, 1.07 to 1.60) in elderly (over 65 years of age). In women aged 50-64, hypertension (OR, 1.39; 95% CI, 1.30 to 1.49), diabetes (OR, 1.51; 95% CI, 1.35 to 1.68), chronic cardiovascular disease (OR, 1.31; 95% CI, 1.05 to 1.64), and hypertension (OR, 1.55; 95% CI, 1.40 to 1.71), diabetes (OR, 1.27; 95% CI, 1.12 to 1.43) in elderly (over 65 years of age).@*CONCLUSIONS@#Populations in aged 50-64 are recommendation subject for vaccination or classified as high-risk group in case with chronic disease. Though subject over 60 years old is age close to the elderly, the coverage rates for vaccination was low. It is necessary to devise strategies to raise the coverage rates for vaccination.

Older Adults' Perception of Chronic Illness Management in South Korea / 예방의학회지

OBJECTIVES: Despite the recent emphasis on a patient-centered chronic care model, few studies have investigated its use in older adults in South Korea. We explored how older Korean adults perceive and cope with their chronic illness. METHODS: We conducted focus group interviews in Seoul, Korea in January 2010. Focus groups were formed by disease type (hypertension and type 2 diabetes) and gender using purposive sampling. Inclusion criteria were patients aged 60 and over who had been diagnosed with diabetes or hypertension and received care at a community health center for at least six months prior to participation. Interview data were analyzed through descriptive content analysis. RESULTS: Among personal factors, most participants felt overwhelmed when they received their diagnosis. However, with time and control of their acute symptoms using medication, their worry diminished and participants tended to denying being identified as a patient or sick person. Among socio-familial factors, participants reported experiencing stigma with their chronic illness and feeling it was a symbol of weakness. Instead of modifying their lifestyles, which might interfere with their social relationships, they resorted to only following their medicine regime prescribed by their doctor. Participants also reported feeling that their doctor only prescribed medications and acted in an authoritative and threatening manner to induce and reinforce participants\' compliance with treatment. CONCLUSIONS: For successful patient-centered management of chronic illnesses, supportive environments that include family, friends, and healthcare providers should be established.

Diabetes Epidemics in Korea: Reappraise Nationwide Survey of Diabetes "Diabetes in Korea 2007"

There are many studies on the prevalence, clinical characteristics, and economic burden of diabetes across the past four decades in Korea. Nonetheless, there is a dearth of nationwide study regarding diabetes encompassing all age group. Eight years ago, the Committee on the Epidemiology of Diabetes Mellitus of Korean Diabetes Association collaborated with Health Insurance Review & Assessment Service to evaluate the status of diabetes care and characteristics in diabetic patients in Korea. In 2007, the collaborative task force team published a comprehensive survey titled "Diabetes in Korea 2007." In this review, we reappraise the diabetic epidemics from the joint report and suggest further studies that are needed to be investigated in the future.

Burden of Ischemic Stroke in Korea: Analysis of Disability-Adjusted Life Years Lost

BACKGROUND AND PURPOSE: Disability-adjusted life years (DALY), incorporating both disability and mortality, has been widely employed to measure regional and global burdens of stroke. Thus far, the DALY lost to stroke in a population has been estimated using only the crude population-level data; no previous study has incorporated refined data from stroke registries. The aim of this study was to integrate the stroke registry data and the population-level incidence data to project the nationwide DALY lost to ischemic stroke. METHODS: From the data of two large ischemic stroke registries, we derived an average DALY lost due to ischemic stroke for each of the following age groups: or =85 years. The nationwide ischemic stroke incidence for each age group was extracted from a cardiovascular and cerebrovascular surveillance study that analyzed the 2004 Korean Health Insurance database. RESULTS: The average DALY lost due to ischemic stroke for the age groups or =85 years was 5.07, 4.63, 4.35, 3.88, 2.88, and 1.73, respectively. By multiplying the incidence and the average DALY lost, the nationwide DALY lost was determined to be 9,952 for those or =85 years, respectively. The projected nationwide DALY lost due to 64,688 ischemic strokes in 2004 was 234,399 (121,482 for men and 113,244 for women), and the DALY lost per 100,000 person-years was 483 (500 for men and 469 for women). CONCLUSIONS: Incidence data from a population study and DALY values derived from stroke registries can be integrated to provide a more refined projection of the nationwide burden of ischemic stroke. In Korea, more than 230,000 years of healthy life are being lost annually due to ischemic stroke, and hence prompt action is imperative.

Continuity of Care for Elderly Patients with Diabetes Mellitus, Hypertension, Asthma, and Chronic Obstructive Pulmonary Disease in Korea

We sought to assess continuity of care for elderly patients in Korea and to examine any association between continuity of care and health outcomes (hospitalization, emergency department visits, health care costs). This was a retrospective cohort study using the Korea National Health Insurance Claims Database. Elderly people, 65-84 yr of age, who were first diagnosed with diabetes mellitus (n=268,220), hypertension (n=858,927), asthma (n=129,550), or chronic obstructive pulmonary disease (COPD, n=131,512) in 2002 were followed up for four years, until 2006. The mean of the Continuity of Care Index was 0.735 for hypertension, 0.709 for diabetes mellitus, 0.700 for COPD, and 0.663 for asthma. As continuity of care increased, in all four diseases, the risks of hospitalization and emergency department visits decreased, as did health care costs. In the Korean health care system, elderly patients with greater continuity of care with health care providers had lower risks of hospital and emergency department use and lower health care costs. In conclusion, policy makers need to develop and try actively the program to improve the continuity of care in elderly patients with chronic diseases.

Patient Assessment of Primary Care of Health Cooperative Clinics in South Korea / 가정의학회지

BACKGROUND: In South Korea, major health care problems have been occurred under the structural background that medical services are mainly provided by private medical institutions. Primary health care, which is very crucial in public health, has been overlooked, and is disorganized and fragmented. In the mean time, health cooperative movement was initiated by local residents and medical doctors to overcome health care problems in 1987. We conducted this study to evaluate the role of health cooperative clinics and obtain lessons for the future primary care policy. METHODS: During April to June in 2007, survey was performed by a trained interviewer at the waiting rooms of 3 health cooperative clinics, in the process of development of the Korean Primary Care Assessment Tool (KPCAT). The KPCAT consists of 5 domains (21 items): first contact (5), coordination function (3), comprehensiveness (4), family/community orientation (4), and personalized care (5). Subjects were patients (or guardians) who had visited their health cooperative clinics on six or more occasions over a period of more than 6 months. We compared primary care scores of each domain between members and non-members of health cooperative clinics by student t-test. Effect of having a membership on each primary care domains was examined by multiple regression analysis. RESULTS: Among the participants (N = 100), members of health cooperatives were 48, and non-members 52. Total average scores of 5 primary care domains of the KPCAT were 78.0 +/- 13.5 on 100 point scale. (82.0 +/- 13.1 in members, and 74.3 +/- 13.0 in nonmembers; P = 0.004) Among primary care domains, personalized care was the highest (91.4 +/- 11.0), and coordination function the lowest (61.0 +/- 33.1) in score. Significant differences between members and nonmembers were noted in coordination function (68.9 vs. 53.7, P = 0.021) and comprehensiveness (78.4 vs. 67.2, P = 0.008). These differences were continued after adjusting by multiple regression analysis for socio-demographic variables including age, sex, income, education, number of disease, and duration since the first visit. CONCLUSION: In the health cooperative clinics whose primary care performance has been considered exemplary in the context of health care in South Korea, primary care scores assessed by members were higher than those by non-members. The significant differences of scores in coordination function and comprehensiveness between members and nonmembers suggest that the future primary care policy should be focused to strengthen these two domains of primary care.

An Evaluation of Sampling Design for Estimating an Epidemiologic Volume of Diabetes and for Assessing Present Status of Its Control in Korea / 예방의학회지

OBJECTIVES: An appropriate sampling strategy for estimating an epidemiologic volume of diabetes has been evaluated through a simulation. METHODS: We analyzed about 250 million medical insurance claims data submitted to the Health Insurance Review & Assessment Service with diabetes as principal or subsequent diagnoses, more than or equal to once per year, in 2003. The database was re-constructed to a 'patient-hospital profile' that had 3,676,164 cases, and then to a 'patient profile' that consisted of 2,412,082 observations. The patient profile data was then used to test the validity of a proposed sampling frame and methods of sampling to develop diabetic-related epidemiologic indices. RESULTS: Simulation study showed that a use of a stratified two-stage cluster sampling design with a total sample size of 4,000 will provide an estimate of 57.04% (95% prediction range, 49.83 - 64.24%) for a treatment prescription rate of diabetes. The proposed sampling design consists, at first, stratifying the area of the nation into "metropolitan/city/county" and the types of hospital into "tertiary/secondary/primary/clinic" with a proportion of 5:10:10:75. Hospitals were then randomly selected within the strata as a primary sampling unit, followed by a random selection of patients within the hospitals as a secondly sampling unit. The difference between the estimate and the parameter value was projected to be less than 0.3%. CONCLUSIONS: The sampling scheme proposed will be applied to a subsequent nationwide field survey not only for estimating the epidemiologic volume of diabetes but also for assessing the present status of nationwide diabetes control.

The Socioeconomic Cost of Injuries in South Korea / 예방의학회지

OBJECTIVES: This study was conducted to estimate the socioeconomic cost of injuries in South Korea. METHODS: We matched claims data from national health insurance, automobile insurance and industrial accident compensation insurance (IACI), and mortality data obtained from the national statistical office from 2001 to 2003 by patients' unique identifier. Socioeconomic cost included both direct cost and indirect cost: the direct cost was injury-related medical expenditure and the indirect cost included loss of productivity due to healthcare utilization and premature death. RESULTS: The socioeconomic cost of injuries in Korea was approximately 1.9% of the GDP from 2001 to 2003. That is, 12.1 trillion KRW (Korean Won) in 2001, 12.3 trillion KRW in 2002, and 13.7 trillion KRW in 2003. In 2003, direct medical costs were 24.6% (3.4 trillion KRW), the costs for loss of productivity by healthcare utilization were 13.0% (1.8 trillion KRW), and the costs for loss of productivity by premature death were 62.4% (8.6 trillion KRW). CONCLUSIONS: In this study, the socioeconomic cost of injuries in Korea between 2001 and 2003 was estimated by using not only health insurance claims data, but also automobile insurance, IACI claims and mortality data. We conclude that social efforts are required to reduce the socioeconomic cost of injuries in Korea, which represented approximately 1.9% of the GDP for the time period specified.

Long-Term Trend in the Incidence of Acute Myocardial Infarction in Korea: 1997-2007

BACKGROUND AND OBJECTIVES: Information about disease incidence is indispensable for the active prevention and control of acute myocardial infarction (AMI). The purpose of this study was to provide basic information for the establishment of policy related to AMI by examining the long-term trends in incidence of AMI. SUBJECTS AND METHODS: This study identified the trend in disease incidence during between 1997 and 2007 using the Korean National Health Insurance Database that includes AMI {the 10th International Classification of Disease (ICD-10) code: I21, I22, I23, I250, I251} as a primary or secondary disease. RESULTS: The attack and incidence rates for AMI in 2007 were 118.4 and 91.8 per 100,000 persons, respectively, and the rates more than doubled for the 11 years. Both rates were higher among males than females and increased more in the older age groups. Incidence cases accounted for most of the total attack cases every year; however, in recent years the proportion of relapse cases was on the rise. The case fatality rate was highest (14.5%) in 2000, and declined rapidly to 9.8% in 2007. The case fatality rate was higher among females than males and the older age groups; in particular, female patients > or=65 years of age had the highest fatality rate. CONCLUSION: This study showed that AMI has been on the rise in Korea for 11 years. Therefore, the establishment of policy for intensive control of the incidence of AMI is necessary by building a continuous monitoring and surveillance system.

Epidemiologic Characteristics of Death by Poisoning in 1991-2001 in Korea

The purpose of this study was to investigate the epidemiologic characteristics of the death by poisoning in Korea. We recoded the Death Certificates Database by injury based on the short version of the International Classification of External Causes of Injuries (ICECI). We evaluated the mortality rate by total injury and poisoning, and analyzed the mortality rate by age, gender, year and month, toxic agent, and intent. Adjusted odds ratios were calculated to evaluate the effects of socioeconomic factors on suicidal poisoning death. The total number of death cases by injury was 346,656. The proportion of death cases by injury decreased from 13.53% of all death cases in 1991 to 11.89% in 2001. However, the mortality rate by poisoning increased rapidly from 1998, and then remained stable. The number of suicidal poisoning deaths has gradually increased, and its mortality rate was 6.41 (per 100,000) in 2001. Major toxic agents were pesticides and herbicides (50.90%) in 2001. Adjusted odds ratios of suicidal poisoning versus other poisonings showed significant differences in education attainment, region, and marital status. In conclusion, the mortality rate by poisoning has increased, and the proportion of suicidal poisoning also has increased compared to that of accidental poisoning.

The Usefulness of the Secondary Database for Occupational Asthma Surveillance System in Korea / 한국역학회지

Occupational asthma is defined as a disease that is characterized by airway narrowing and bronchial hyperresponsiveness caused by specific working environment. It is estimated that occupational asthma cases in Korea have been underreported. This study, using Korean Medical Insurance Data(KMID), examined the distribution of asthma patients' occupations and the frequency of high risk occupations for occupational asthma in Seoul, Korea to evaluate the usefulness of the KMID data as a database for active occupational asthma surveillance system. Six hundreds and forty two(30.7%) of 2093 patients who were finally chosen as a study population by using 1995-year KMID, were contacted by telephone. 296 persons(47.4%) of 642 patients replied that they were diagnosed as asthma. The occupations of 296 asthma patients were classified by Korean standardized industrial classfication (KSIC). The most common occupations included Wholesale and Retail trade(19.5%), Real estate, Renting and Business activities(14.9%), Construction(14.9%), Manufacturing(12.3%). Forty(13.5%) of 296 patients who could be classified by KSIC were working at high risk jobs for occupational asthma. KMID could be used as a useful data for occupational asthma surveillance system if the limitations of KMID, which is the accuracy of diagnosis, data accessibility, difficulty of following up study subjects, would be solved. The prevalence of occupational asthma could be estimated if the follow-up study diagnosing occupational asthma for asthma patients working in high risk jobs would be held.

Occupational Cancer Surveillance System Using Data Linkage Analysis in Korea / 한국역학회지

To develop the occupational cancer surveillance system in Korea, data linkage analysis was performed on the subjects of Health-monitoring-pocketbook (the list of subjects who were exposed to selected occupational carcinogens) and the retired workers of a cokes manufacturing factory using the Korean medical insurance data, Korean death certificate data and Korean cancer registry data. Study subjects comprised the 822 retired subjects and the 3101 present-post subjects of Health-monitoring-pocketbook and the 182 retired workers of a cokes manufacturing factory. The incidence of cancer of these study subjects was ascertained by linkage of Korean medical insurance data of year 1995-6, Korean death certificate data of year 1992-8 and Korean cancer registry data of year 1993-5. In the study subjects, Eighty seven percent were males and mean age was 39.3+/-8.9 year-old, Average work duration was 8.0+/-5.5 years. Chrome, asbestos and cokes were the most frequent exposed agents. In the study subjects, total 13 cancer cases were ascertained by data linkage analysis. In the ascertained cancer cases, 8 cases were male and 5 cases were female, and 7 cases were aged 40-49 yr, 5 cases were aged 50-59 yr and 1 cases were aged 30-39 yr. The commonest exposure agent in the ascertained cancer cases was asbestos and cokes. By the site of cancer, 3 stomach cancer cases, 2 hematopoietic cancer cases and 2 biliary tract cancer cases were ascertained. The occupational cancer surveillance system using data linkage analysis on the workers exposed to hazardous agents was the most feasible and efficient method in Korea. And to do this, establishment of occupational history information in several disease registry database is needed with the effort of estimating the proper size of workers exposed hazardous agents.

Measurement Errors on Normotensive Subjects in Screening Test / 한국역학회지

BACKGROUND: Blood pressure measurements with a mercury sphygmomanometer serve as the screening test to establish the clinical diagnosis of primary hypertension. But one of the problems of hypertension screening is the variability of blood pressure measurements. METHODS: In order to identify the measurement error of blood pressure through the biennial health screening program of Korea Insurance Medical Corporation, we compared the blood pressure of screening test with true value which defined as the mean of blood pressures taken from the direct contact and twice check-up among normotensive Seoul Cohort participants. RESULTS: Three hundred forty-nine participants had both data of screening measurement and survey of direct contact. The means of difference in systolic and diastolic blood pressure between both data were 8.47 mmHg and 6.54 mmHg, respectively. These results showed statistical significance with paired t-test (p=0.001). CONCLUSION: Our findings indicated that screening measurement of blood pressure had false negative. And if a epidemiologic study about blood pressure used the data of screening test, it should adjust value of systolic and diastolic blood pressure with adding 8 and 7 mmHg, respectively.

Development of Work-related Musculoskeletal Disorder Questionnaire Using Receiver Operating Characteristic Analysis / 예방의학회지

OBJECTIVES: Receive Operating Characteristic(ROC) curve with the area under the ROC curve(AUC) is one of the most popular indicator to evaluate the criterion validity of the measurement tool. This study was conducted to develop a standardized questionnaire to discriminate workers at high-risk of work-related musculoskeletal disorders using ROC analysis. METHODS: The diagnostic results determined by rehabilitation medicine specialists in 370 persons(89 shipyard CAD workers, 113 telephone directory assistant operators, 79 women with occupation, and 89 housewives) were compared with participant's own replies to 'the questionnair on the worker's subjective physical symptoms'(Kwon, 1996). The AUC's from four models with different methods in item selection and weighting were compared with each other. These 4 models were applied to 225 persons, working in an assembly line of motor vehicle, for the purpose of AUC reliability test. RESULTS: In a weighted model with 11 items, the AUC was 0.8155 in the primary study population, and 0.8026 in the secondary study population(p=0.3780). It was superior in the aspects of discriminability, reliability and convenience. A new questionnaire of musculoskeletal disorder could be constructed by this model. CONCLUSION: A more valid questionnaire with a small number of items and the quantitative weight scores useful for the relative comparisons are the main results of this study. While the absolute reference value applicable to the wide range of populations was not estimated, the basic intent of this study, developing a surveillance tool through quantitative validation of the measures, would serve for the systematic disease prevention activities.