Policy Review and Modeling Analysis of Mitigation Measures for Coronavirus Disease Epidemic Control, Health System, and Disease Burden, South Korea.

We reviewed the timeline of key policies for control of the coronavirus disease epidemic and determined their impact on the epidemic and hospital burden in South Korea. Using a discrete stochastic transmission model, we estimated that multilevel policies, including extensive testing, contact tracing, and quarantine, reduced contact rates by 90% and rapidly decreased the epidemic in Daegu and nationwide during February‒March 2020. Absence of these prompt responses could have resulted in a >10-fold increase in infections, hospitalizations, and deaths by May 15, 2020, relative to the status quo. The model suggests that reallocation of persons who have mild or asymptomatic cases to community treatment centers helped avoid overwhelming hospital capacity and enabled healthcare workers to provide care for more severely and critically ill patients in hospital beds and negative-pressure intensive care units. As small outbreaks continue to occur, contact tracing and maintenance of hospital capacity are needed.

Characteristics in Pediatric Patients with Coronavirus Disease 2019 in Korea.

BACKGROUND: Based on the reports of low prevalence and severity of pediatric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, the Korean government has released new SARS-CoV-2 infection response and treatment guidelines for children under the age of 12 years. The government has further directed school reopening under strict preventive measures. However, there is still considerable concern on the impact of school reopening on community transmission of Coronavirus disease 2019 (COVID-19). In the present study, we aimed to evaluate the appropriateness of these directives and the severity of SARS-CoV-2 infections in children as compared to adults using sufficient national sample data. METHODS: In the present study, we evaluated the severity of SARS-CoV-2 infection in pediatric patients as compared to adults by analyzing the length of hospital stays (LOS), medical expenses, and hospital and intensive care unit (ICU) admission rates. A multivariate linear regression analysis was carried out to examine the effects of COVID-19 patients that the characteristics on the LOS and medical expenses, and multivariate logistic regression analysis were performed to identify COVID-19 characteristics that affect hospital and ICU admission rates and to prove the low SARS-CoV-2 infection severity in pediatric patients. RESULTS: The hospitalization period for children aged 0-9 was 37% shorter and that of patients aged 10-19 years was 31% shorter than those of older age groups (P < 0.001). The analysis of the medical expenses by age showed that on average, medical expenses for children were approximately 4,900 USD lower for children than for patients over 80 years of age. The linear regression analysis also showed that patients who were 0-9 years old spent 87% and those aged 10-19 118% less on medical expenses than those aged 70 and over, even after the correction of other variables (P < 0.001). The probability of hospitalization was the lowest at 10-19 years old (odds ratio [OR], 0.05; 95% confidence interval [CI], 0.03-0.09), and their ICU admission rate was also the lowest at 0.14 (OR, 0.14; 95% CI, 0.08-0.24). On the other hand, the likelihood of hospitalization and ICU admission was the highest in children aged 0-9 years, and among patients under the age of 50 years in general. CONCLUSION: This study demonstrated the low severity of SARS-CoV-2 infection in younger patients (0-19 years) by analyzing the LOS, medical expenses, hospital, and intensive care unit admission rates as outcome variables. As the possibility to develop severe infection of coronavirus at the age of 10-19 was the lowest, a mitigation policy is also required for middle and high school students. In addition, children with underlying diseases need to be protected from high-risk infection environments.

Risk Factors of Outcomes of COVID-19 Patients in Korea: Focus on Early Symptoms.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has spread around the globe, and it is important to determine the risk factors of death in the general population. Our study aimed to determine the risk factors of death and severe illness requiring supplemental oxygen therapy based on the demographic and clinical characteristics of COVID-19 patients in Korea. METHODS: In this study, we used data provided by the Korea Disease Control and Prevention Agency (KDCA) and analyzed a total of 5,068 patients with COVID-19, excluding 19 pregnant women and 544 individuals with missing data. We performed logistic regression analysis to determine the impact of early symptoms on survival and severe disease. Logistic regression models included sex, age, number of comorbidities, symptoms on admission, blood pressure, heart rate, and body temperature as explanatory variables, and death and oxygen therapy as outcome variables. RESULTS: Logistic regression analyses revealed that the male sex, older age (≥ 60 years), higher number of comorbidities, presence of symptoms on admission, heart rate ≥ 120 bpm, and body temperature ≥ 37.5°C presented with higher risk of in-hospital death and oxygen therapy requirement. Conversely, rhinorrhea and headache were associated with a low risk of death and oxygen therapy requirement. The findings showed that cough, sputum, and fever were the most common symptoms on admission, while 25.3% of patients with COVID-19 were asymptomatic. CONCLUSION: COVID-19 patients with high-risk early symptoms on admission, such as dyspnea and altered mental status, and those without low-risk symptoms of rhinorrhea and headache should be included in priority treatment groups.

Influencing Factors of Transportation Costs Regarding Healthcare Service Utilization in Korea.

BACKGROUND: Transportation costs can be a barrier to healthcare services, especially for low-income, disabled, elderly, and geographically isolated populations. This study aimed to estimate the transportation costs of healthcare service utilization and related influencing factors in Korea in 2016. METHODS: Transportation costs were calculated using data from the 2016 Korea Health Panel Study. A total of 14,845 participants were included (males, 45.07%; females, 54.93%), among which 2,148 participants used inpatient and 14,787 used outpatient care services. Transportation costs were estimated by healthcare types, transportation modes, and all disease and injury groups that caused healthcare service utilization. The influencing factors of higher transportation costs were analyzed using multivariable regression analysis. RESULTS: In 2016, the average transportation costs were United States dollars (USD) 43.70 (purchasing power parity [PPP], USD 32.35) per year and USD 27.67 (PPP, USD 20.48) per visit for inpatient care; for outpatient case, costs were USD 41.43 (PPP, USD 30.67) per year and USD 2.09 (PPP, USD 1.55) per visit. Among disease and injury groups, those with neoplasms incurred the highest transportation costs of USD 9.73 (PPP, USD 7.20). Both inpatient and outpatient annual transportation costs were higher among severely disabled individuals (inpatient, +USD 44.71; outpatient, +USD 23.73) and rural residents (inpatient, +USD 20.40; outpatient, +USD 28.66). Transportation costs per healthcare visit were influenced by healthcare coverage and residential area. Sex, age, and income were influencing factors of higher transportation costs for outpatient care. CONCLUSION: Transportation cost burden was especially high among those with major non-communicable diseases (e.g., cancer) or living in rural areas, as well as elderly, severely disabled, and low-income populations. Thus, there is a need to address the socioeconomic disparities related to healthcare transportation costs in Korea by implementing targeted interventions in populations with restricted access to healthcare.

Comparative analysis of genetic testing utilization rates among people with and without disabilities in South Korea from 2016 to 2019, focusing on malignant neoplasms: A national population-based study.

INTRODUCTION: Oncogene testing is widely used to detect or direct cancer treatments. Compared to people without disabilities, people with disabilities in Korea have a lower cancer incidence rate but a fivefold higher cancer mortality rate, implying delayed detection. METHODS: We used an administrative database combining disability status and care utilization to analyze every case of cancer-related genetic testing paid for by the National Health Insurance Services of Korea between 2016 and 2019. We first compared percentages of individuals who had taken a registered genetic test by their disability statuses. We then compared the most frequently utilized tests between individuals with and without disabilities. RESULTS: Korean citizens, 175,000 in total, underwent at least one of the 192 registered cancer-related genetic tests between 2016 and 2019. People with disabilities utilized these genetic tests at higher rates than those without disabilities, regardless of sex or age. Among people aged ≥40 years, lung and colorectal cancer-related tests were most frequently utilized, regardless of disability status. CONCLUSION: Although the cancer-related genetic test uptake rate is higher among people with disabilities than among those without disabilities, it is still possible that information on these tests is not as readily available to people with disabilities. Therefore, it is imperative for the government to actively devise strategies to enhance national cancer screening rates among people with disabilities.

Increased risk of SARS-CoV-2 infection and COVID-19 death among older patients at long-term care hospitals in Korea.

Introduction: Long-term care hospitals are known to be vulnerable to SARS-CoV-2 infection and death given their numerous older chronic disease patients. However, the actual effect of long-term care hospital admission is not well known in Korea; hence, this study sought to analyze the effect of long-term care hospitalization on SARS-CoV-2 infection and COVID-19 death by correcting for patients' characteristics. Methods: This cross-sectional study used the data from K-COV-N cohort, which is linked to the National Health Insurance Service and the Korea Disease Control and Prevention Agency; it analyzed 70,373 individuals aged ≥60 years, who had been tested for COVID-19 between January 1 and May 30, 2020 (KDCA-NHIS-2020-1-601). Patients admitted to a long-term care hospital were defined as those with a confirmed history of hospitalization within 30 days of the COVID-19 testing date. The final data analysis was performed in December 2022. Logistic regression analysis of the national data was employed to determine the association between long-term care hospital admission, the risk of SARS-CoV-2 infection, and death from COVID-19. The odds ratios for SARS-CoV-2 infection and death from COVID-19 were calculated by adjusting for sex, age, residential area, health insurance premium, disability, and the Charlson Comorbidity Index. Results: Older patients at long-term care hospitals had a high risk of SARS-CoV-2 infection (OR:2.91, 95% CI:2.33-3.64) and death from COVID-19 (OR:3.58, 95% CI:2.13-6.02). A difference in SARS-CoV-2 infection risk was observed based on residential area, health insurance premium (economic level), and disability; no difference was observed for COVID-19 mortality risk. Discussion: Admission to a long-term care hospital itself could be a risk factor for SARS-CoV-2 infection and the consequent high mortality risk after adjusting for sex, age, disability, and comorbidities. Patients are at high risk of infection through contact with workers, leading to death; therefore, quarantine policies for workers must be strengthened.

Association of Metabolic Syndrome with COVID-19 in the Republic of Korea.

BACKGROUND: Metabolic syndrome (MetS) is reportedly a crucial risk factor for coronavirus disease 2019 (COVID-19). Since the epidemiological studies that examine this association are few and include small samples, we investigated the relationship between MetS and COVID-19 severity and death using a larger sample in the Republic of Korea. METHODS: We analyzed 66,321 patients, 4,066 of whom had COVID-19. We used chi-square tests to examine patients' characteristics. We performed logistic regression analysis to analyze differences in COVID-19 infection and clinical outcomes according to the presence of MetS. RESULTS: Although MetS was not significantly associated with COVID-19 risk, acquiring MetS was significantly associated with the risk of severe COVID-19 outcomes (odds ratio [OR], 1.97; 95% confidence interval [CI], 1.34 to 2.91; P=0.001). The mortality risk was significantly higher in COVID-19 patients with MetS (OR, 1.74; 95% CI, 1.17 to 2.59; P=0.006). Patients with abnormal waist circumference were approximately 2.07 times more likely to develop severe COVID-19 (P<0.001), and high-density lipoprotein cholesterol (HDL-C) levels were significantly associated with COVID-19; the mortality risk due to COVID-19 was 1.74 times higher in men with an HDL-C level of <40 mg/dL and in women with an HDL-C level of <50 mg/dL (P=0.012). CONCLUSION: COVID-19 is likely associated with severity and death in patients with MetS or in patients with MetS risk factors. Therefore, patients with MetS or those with abnormal waist circumference and HDL-C levels need to be treated with caution.

Exposure to COVID-19 Infection and Mortality Rates Among People With Disabilities in South Korea.

BACKGROUND: With the delayed eradication of coronavirus disease 2019 (COVID-19), people with disabilities, a socially vulnerable class of individuals, face aggravated hardships caused by a pause in support services and lack of care due to stricter social distancing policies combined with the challenges of their disabilities. Given this background, we aim to investigate COVID-19 infection and mortality rates among people with disabilities, who face heightened physical and mental health threats amidst the COVID-19 pandemic. METHODS: Gender, age, health insurance premiums, the Charlson Comorbidity Index (CCI), the severity of the disability, and the type of disability were compared among people with disabilities who had been infected with or died from COVID-19 using the nationally representative National Health Insurance Service (NHIS)-COVID-19 database (DB). RESULTS: We found that the COVID-19 infection rate was higher among those with low income, those with severe disability, and those with "other" disabilities (ie, speech disabilities, hepatic dysfunction, respiratory dysfunction, facial disfigurement, intestinal fistular/urinary disability, epilepsy, intellectual disability, autistic disorder, and mental disorders). The mortality rate was markedly higher (ie, 15.90 times higher, odds ratio [OR]: 15.90, 95% confidence interval [CI]: 6.16 - 41.06) among people aged 80 years or older as compared with those aged 60 years or younger. The odds for mortality were 2.49 times higher (OR: 2.49, 95% CI: 1.33 - 4.64) among people with severe disabilities as compared with mild disabilities. CONCLUSION: Among people with disabilities, we found that COVID-19 infection rates differed according to income level, severity of the disability, and disability type, while the COVID-19 mortality rates differed according to age and severity of the disability.

COVID-19 Disease Burden Related to Social Vulnerability and Comorbidities: Challenges to Tuberculosis Control.

Purpose: The first coronavirus disease (COVID-19) spike and subsequent pandemic in South Korea were rapid and disruptive. Government response measures for disadvantaged groups against infectious disease should be prioritized based on evidence and affordability. We investigated whether COVID-19 infection, intensive care unit (ICU) care, and mortality from COVID-19 are related to social and medical vulnerability, including tuberculosis (TB). Patients and Methods: Using the National Health Insurance Service COVID-19 database in South Korea, we analyzed 129,128 patients, including controls, from 1 January to 30 May 2020, during the early stage of the COVID-19 epidemic. The relationship between health insurance premiums (representing socioeconomic status), the Charlson comorbidity index (CCI) score for the severity of the underlying disease, and additional TB diagnosis was analyzed using the chi-square test and logistic regression. Results: For the demographics, 3244 out of 51,783 men (6.3%) and 4836 out of 77,345 women (6.3%) were infected with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). COVID-19 infection, ICU care, and mortality were related to older age (p < 0.001) and lower health insurance premium levels (p < 0.05). Regarding the CCI score, the CCI score, COVID-19 infection, and mortality increased (p < 0.0001). In terms of premium level, the highest group showed a lower risk of infection (OR 0.52, 0.48-0.57, p = 0.004), ICU care (OR 0.59, 0.46-0.75, p < 0.001), and mortality (OR 0.51, 0.32-0.78, p = 0.016) than the medical aid group. TB was related to ICU care for COVID-19 (OR 4.27, 1.27-14.38, p = 0.018). Conclusion: In the early epidemic, SARS-CoV-2 infection, ICU admission, and mortality from COVID-19 increased in socioeconomically and physically vulnerable groups. However, the relationship between tuberculosis, COVID-19 and mortality was not definite because of the possible under-reporting of TB cases and the relatively small number of TB patients.

A National Study of Life-Sustaining Treatments in South Korea: What Factors Affect Decision-Making?

PURPOSE: This cross-sectional study investigated the status of life-sustaining treatment (LST) practices and identified characteristics and factors influencing decision-making practices. MATERIALS AND METHODS: The National Agency for Management of Life-sustaining Treatment retains records provided by doctors regarding patients subject to LST implementation. A total of 71,327 patients receiving LST were identified. We analyzed all nationally reported data between February 2018 and October 2019. Indicators such as the proportion of deaths, records for decision to terminate LST, implementation of LST records, and registration of Advance Statements on LST were analyzed. RESULTS: A total of 67,252 (94.3%) end-of life decisions were implemented in South Korea. The proportion of deaths preceded by a LST plan, non-self-determination LST decision, and any advance statements was 33.5% (23,891/71,327), 66.5% (47,436/71,327), and 1.2% (890/71,327), respectively. The logistic regression model revealed that self-determination to terminate LST was more frequent for men than for women and higher for those aged 30-69. Disability (odds ratio [OR], 0.59; 95% confidence interval [CI], 0.56 to 0.61), living in non-metropolitan areas (OR, 0.84; 95% CI, 0.81 to 0.86), and disease comorbidity was independently associated with a low level of self-determination. CONCLUSION: After the implementation of the new LST Act, about a third of patients in end-of-life process made decisions regarding their medical LST. However, family members still play a major role in LST decisions where the patient's intention cannot be verified. Decisions related to LST are predominantly made when death is imminent. Thus, it is necessary to increase awareness of end-of-life LST decision-making among medical staff and the public.

Comorbidities and Factors Determining Medical Expenses and Length of Stay for Admitted COVID-19 Patients in Korea.

PURPOSE: No previous investigations of coronavirus disease 2019 (COVID-19) have estimated medical expenses, length of stay, or factors influencing them using administrative datasets. This study aims to fill this research gap for the Republic of Korea, which has over 10,000 confirmed COVID-19 cases. PATIENTS AND METHODS: Using the nationwide health insurance claims data of 7590 confirmed COVID-19 patients, we estimated average medical expenses and inpatient days per patient, and performed multivariate negative binomial, and gamma regressions to determine influencing factors for higher outcomes. RESULTS: According to the results, COVID-19 patients with history of ICU admission, chest CT imaging, lopinavir/ritonavir and hydroxychloroquine use stayed longer in the hospital and spent more on medical expenses, and anti-hypertensive drugs were insignificantly associated with the outcomes. Female patients stayed longer in the hospital in the over 65 age group but spent less in medical expenses that the 20-39 group. In the 40-69 age group, patients with health insurance stayed longer in the hospital and spent more on medical expenses than those aged over 65 years. Comorbidities did not affect outcomes in most age groups. CONCLUSION: In summary, contrary to popular beliefs, medical expenses and length of hospitalization were mostly influenced by age, and not by comorbidities, anti-viral, or anti-hypertensive drugs. Thus, responses should focus on infection prevention and control rather than clinical countermeasures.

The Relationship Between Socio-Demographic Factors and Tuberculosis Mortality in the Republic of Korea During 2008-2017.

The Republic of Korea has a high incidence of tuberculosis (TB) and TB-specific mortality rate. In 2019, it had the second highest TB-specific mortality among Organization for Economic Co-operation and Development countries. Understanding the factors associated with TB-specific deaths may help eradicate the disease. Therefore, we aimed to identify the general characteristics associated with TB-specific mortality among Koreans. Using Causes of Death Statistics data from Statistics Korea, we assessed the year of death, sex, age, occupation, area of residence, marital status, and education level reported between 2008 and 2017. Patient characteristics associated with TB-specific deaths were analyzed using the Chi-squared test, while influencing factors of TB-specific mortality were analyzed using logistic regression analysis to calculate adjusted odds ratios (AOR). Female (AOR: 0.509, 95% CI: 0.493-0.526), those with a graduate degree or higher (AOR: 0.559, 95% CI: 0.474-0.660) had lower TB-specific mortality rates than those of their counterparts. Conversely, those aged ≥70 years (AOR: 1.239, 95% CI: 1.199-1.280), single (AOR: 1.355, 95% CI: 1.315-1.396), and skilled agricultural, forestry, and fishery workers (AOR: 1.441, 95% CI: 1.359-1.529) had higher TB-specific mortality rates than those of their counterparts. In conclusion, TB-specific mortality rates differed according to the characteristics of the deceased patients. In order to establish effective TB control, multisectoral action on broader determinants should be strengthened.

Analysis of Risk Factors on Readmission Cases of COVID-19 in the Republic of Korea: Using Nationwide Health Claims Data.

In South Korea, 4.5% patients of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were readmitted to hospitals after discharge. However, there is insufficient research on risk factors for readmission and management of patients after discharge is poor. In this study, 7590 confirmed coronavirus disease (COVID-19) patients were defined as a target for analysis using nationwide medical claims data. The demographic characteristics, underlying diseases, and the use of medical resources were used to examine the association with readmission through the chi-square test and then logistic regression analysis was performed to analyze factors affecting readmission. Of the 7590 subjects analyzed, 328 patients were readmitted. The readmission rates of men, older age and patients with medical benefits showed a high risk of readmission. The Charlson Comorbidity Index score was also related to COVID-19 readmission. Concerning requiring medical attention, there was a higher risk of readmission for the patients with chest radiographs, computed tomography scans taken and lopinavir/ritonavir at the time of their first admission. Considering the risk factors presented in this study, classifying patients with a high risk of readmission and managing patients before and after discharge based on priority can make patient management and medical resource utilization more efficient. This study also indicates the importance of lifestyle management after discharge.

Duplicated tramadol use in chronic low back pain: A nationwide cross-sectional study.

Tramadol is a weak opioid that is commonly used for chronic low back pain (LBP). Despite its effectiveness, duplicated use of tramadol, which may indicate abuse or dependence, may exacerbate potential adverse reactions. This population-based, cross-sectional study aimed to investigate the prevalence of duplication of tramadol and its associated factors among patients with LBP. From a Korean nationwide claims database, non-hospitalized patients aged 40-99 years with LBP without malignancy were prescribed tramadol during 2014-2016. Duplication of tramadol was defined as overlapping of prescription days. Among them, we defined "extensive duplication (ED)" when days of tramadol duplication cover 10% or more of the days prescribed tramadol. Patient and healthcare utilization factors associated with ED were examined using a logistic regression model. The study population was 6 417 503 patients. Of these, 13.7% were ED users. The age- and sex-standardized prevalence of using tramadol twice or more a year was 14.06 per 100 people in 2014, 13.74 per 100 people in 2015 and 13.52 per 100 people in 2016. ED occurred more in those in the group aged 70-79 years (OR 1.12, 95% CI 1.11-1.13) than 40-49 years and in those with comorbidities, such as drug abuse (OR 2.99, 95% CI 2.05-4.36) or depression (OR 1.75, 95% CI 1.72-1.77). Based on the results of this study, a proper management system is needed to avoid tramadol duplication among older people and patients with drug abuse or depression.

Intensive Care Unit Capacity and Its Associated Risk Factors During the COVID-19 Surge in the Republic of Korea: Analysis Using Nationwide Health Claims Data.

OBJECTIVE: To identify risk factors for intensive care unit (ICU) admission and mechanical ventilator usage among confirmed coronavirus disease (COVID-19) patients and estimate the effects of mitigation efforts on ICU capacity in Korea. PATIENTS AND METHODS: Data on profiles and medical history of all confirmed COVID-19 patients in the past 1 year were extracted from the Korean National Health Insurance System's claims database to assess risk factors for ICU admission and ventilator use. We used a time-series epidemic model to estimate the ICU census in Daegu from the reported hospital data. FINDINGS: Multivariate regression analysis revealed male sex, old age, and residing in Daegu city as significant risk factors for ICU admission. The number of patients requiring ICU admission exceeded the bed capacity across all Daegu hospitals before March 9, 2020, and therefore, critically ill patients were transferred to nearby hospitals outside Daegu. This finding was consistent with our prediction that the ICU census in Daegu would peak on March 16, 2020, at 160 through mitigation efforts, without which it would have reached 300 by late March 2020. CONCLUSION: Older age and male sex were risk factors for ICU admission. In addition, the geographic location of the hospital seems to contribute to the severity of the COVID-19 patients admitted to the ICU and to the ICU capacity.

Factors associated with potentially harmful drug-drug interactions in older Korean people: A population-based study.

AIM: The present study investigated the status of potentially harmful drug-drug interactions (PHDI) in older adults, to obtain insight into factors that influence the risk of PHDI. METHODS: The present study included Korean people aged ≥65 years who were prescribed one or more drugs included in the list of PHDI under the Beers Criteria 2015 from January to December, 2016 (n = 1 257 317). PHDI were defined based on the Beers Criteria 2015. Among 10 PHDI, a prevalence of >5% was taken to be clinically significant, and the relationships between multiple variables and PHDI were examined. RESULTS: The most frequent PHDI was corticosteroids and non-steroidal anti-inflammatory drugs (n = 259 499, 20.64%), followed by a combination of two or more anticholinergic drugs (n = 139 622, 11.1%), and three or more drugs acting on the central nervous system (n = 86 023, 6.84%). These three types of PHDI were more frequent in women (OR 1.066-1.141) and medical aid beneficiaries (OR 1.095-1.510). The risk of PHDI increased in proportion to the number of healthcare institutions used by the participants and their outpatient visits during the year (OR 1.043-1.079, 1.008-1.010, respectively). The risk of PHDI was low when patients took no more than five medications in a single prescription (OR 0.017-0.791). CONCLUSIONS: The findings of the present study highlight the three most frequent PHDI in Korea according to the Beers Criteria 2015. Healthcare providers should take PHDI into account when treating female patients, medical aid beneficiaries, patients using multiple healthcare institutions, frequent outpatient visitors and patients prescribed more than six medications in a single prescription. Geriatr Gerontol Int 2018; 18: 1378-1382.