• Journal of Preventive Medicine and Public Health
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• v.53 no.1
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• pp.56-63
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• 2020

Objectives: The objective of this study was to determine the effect of atrial fibrillation (AF) on the risk of dementia in the Korean elderly. Methods: A 10-year retrospective cohort study was conducted using the National Health Insurance Service-Senior Cohort database. We excluded those who were under 65 years of age as of January 2006 (n=46 113), those who were diagnosed with dementia between 2002 and 2005 (n=9086), and those with a history of stroke prior to AF diagnosis (n=8392). We used a Cox proportional hazards model with a time-varying covariate to determine whether AF is associated with the risk of dementia after adjusting for potential confounders. Results: In univariable Cox regression, the hazard ratio (HR) of dementia according to AF status was 1.28 (95% confidence interval [CI], 1.23 to 1.33). After adjusting for potential confounders, AF was found to increase the risk of dementia (HR, 1.12; 95% CI, 1.07 to 1.17), Alzheimer dementia (HR, 1.12; 95% CI, 1.07 to 1.17), and vascular dementia (HR, 1.10; 95% CI, 1.03 to 1.18). In patients diagnosed with AF, the incidence of dementia was lower (HR, 0.50; 95% CI, 0.47 to 0.52) in patients who were treated with oral anticoagulants. Conclusions: Investigating the potential risk factors of dementia in an aged society is important. We found a slightly higher risk of dementia in those with AF than in those without AF, and we therefore concluded that AF is a potential risk factor for dementia.

• Korean Journal of Clinical Pharmacy
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• v.29 no.3
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• pp.186-192
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• 2019

Background: Diabetes is associated with cancer risk in the aging population. Observational studies have indicated the beneficial effects of metformin against breast cancer, making studies on the anticancer potential of antidiabetic drugs worthwhile. This study investigated cancer incidence in patients on antidiabetic monotherapy. Methods: Using National Health Insurance Service data (2002-2013), a retrospective cohort study that included type 2 diabetes mellitus (T2DM) patients was conducted. Study subjects were enrolled if they were ${\geq}30$ years old, on monotherapy for diabetes, and cancer-free. They were followed up for cancer occurrence or death, until December 31st, 2013. A Cox proportional hazard model analysis was conducted between metformin and sulfonylurea (including meglitinide) users, to determine cancer risk, with adjustment for age, gender, comorbidity index, dyslipidemia, hypertension, and T2DM duration. Results: The number of antidiabetic monotherapy-treated T2DM patients without a history of cancer was 9,554 (metformin, n = 5,825; sulfonylurea, n = 3,225; others, n = 504). During the follow-up period (mean, 2.04; IQR, 3.18 years), the cancer incidence rate was 5.48/100 and 5.45/100 patient-years for metformin and sulfonylurea, respectively. The hazard ratio (HR) for risk of cancer incidence in the metformin group was 0.74 (95% confidence interval [CI], 0.66-0.83; p < 0.0001), compared with sulfonylurea. Additionally, the HRs for risks of lung, liver, and stomach cancer were respectively 0.46 (95% CI, 0.31-0.66; p < 0.0001), 0.41 (95% CI, 0.31-0.54; p < 0.0001), and 0.51 (95% CI, 0.35-0.73; p = 0.0003). Conclusion: Antidiabetic therapy with metformin reduces cancer risk by 26%, specifically for lung, liver, and stomach cancer.

• Health Policy and Management
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• v.28 no.1
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• pp.53-69
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• 2018

Background: This study investigates association modified category medical specialization (CMS) and hospital charge, length of stay (LOS), and mortality among lumbar spine disease inpatients. Methods: This study used National Health Insurance Service-cohort sample database from 2002 to 2013, using stratified representative sampling released by the National Health Insurance Service. A total of 56,622 samples were analyzed. The primary analysis was based on generalized estimating equation model accounting for correlation among individuals within each hospital. Results: Inpatients admitted with lumbar spine disease at hospitals with higher modified CMS had a shorter LOS (estimate, -1.700; 95% confidence interval [CI], -1.886 to -1.514; p<0.0001). Inpatients admitted with lumbar spine disease at hospitals with higher modified CMS had a lower mortality rate (odds ratio, 0.635; 95% CI, 0.521 to 0.775; p<0.0001). Inpatients admitted with lumbar spine disease at hospitals with higher modified CMS had higher hospital cost per case (estimate, 192,658 Korean won; 95% CI, 125,701 to 259,614; p<0.0001). However, inpatients admitted with lumbar spine surgery patients at hospitals with higher modified CMS had lower hospital cost per case (estimate, -152,060 Korean won; 95% CI, -287,236 to -16,884; p=0.028). Inpatients admitted with lumbar spine disease at hospitals with higher modified CMS had higher hospital cost per diem (estimate, 55,694 Korean won; 95% CI, 46,205 to 65,183; p<0.0001). Conclusion: Our results showed that increase in hospital specialization had a substantial effect on decrease in hospital cost per case, LOS, and mortality, and on increase in hospital cost per diem among lumbar spine disease surgery patients.

• Health Policy and Management
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• v.28 no.2
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• pp.168-177
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• 2018

Background: This study investigates the potential volume and outcome association of coronary heart disease (CHD) patients who have undergone percutaneous coronary intervention (PCI) using a large and representative sample. Methods: We used a National Health Insurance Service-Cohort Sample Database from 2002 to 2013 released by the Korean National Health Insurance Service. A total of 8,908 subjects were analyzed. The primary analysis was based on Cox proportional hazards models to examine our hypothesis. Results: After adjusting for confounders, the hazard ratio of thirty-day and 1-year mortality in hospitals with a low volume of CHD patients with PCI was 2.8 and 2.2 times higher (p=0.00) compared to hospitals with a high volume of CHD patients with PCI, respectively. Thirty-day and 1-year mortality of CHD patients with PCI in low-volume hospitals admitted through the emergency room were 3.101 (p=0.00) and 2.8 times higher (p=0.01) than those in high-volume hospitals, respectively. Only 30-day mortality in low-volume hospitals of angina pectoris and myocardial infarction patients with PCI was 5.3 and 2.4 times those in high-volume hospitals with PCI, respectively. Conclusion: Mortality was significantly lower when PCI was performed in a high-volume hospital than in a low-volume hospital. Among patients admitted through the emergency room and diagnosed with angina pectoris, total PCI volume (low vs. high) was associated with significantly greater cardiac mortality risk of CHD patients. Thus, There is a need for better strategic approaches from both clinical and health policy standpoints for treatment of CHD patients.

• Journal of Preventive Medicine and Public Health
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• v.32 no.4
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• pp.513-525
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• 1999

Objectives : High-normal blood pressure' is a factor influencing decision to initiate targeted intensive intervention strategy in westernized populations. JNC-VI offered the vigorous lifestyle modification for persons with 'high-normal blood pressure', who could be early detected. As a hypertension seems to be the result of multiple genetic factors operating in concert with associated environmental factors, it will be necessary to identify the high-normal blood pressure as a risk factor of hypertension for applying primary prevention strategy in Korean people. Methods : Although cohort study design might be adequate to recruit incidence cases, to keep time sequence of events, and to prevent information bias, nested case-control study was chosen for avoiding measurement errors because hypertension is a benign disease. Source population was the 'Seoul Cohort' participants and follow-up was done by using Korea Medical Insurance Corporation's database on the utilization of health services from 1 Jan93 to 30Jun97. Incidence cases were ascertained through the chart review, telephone contacts, and direct blood pressure measurements. Controls included the pairing of 4 individuals to each case on the basis of age. Results : As 75% of 247 incident cases had high-normal blood pressure, the crude odds ratio for hypertension was 2.04 (95% CI 1.47-2.83). Another statistically significant risk factors of hypertension were body mass index, dietary fiber, alcohol consumption, weekly activity and history of quitting smoking. The multivariate odds ratio of high-normal blood pressure adjusted for all risk factors was 1.84 (95% CI 1.31-2.56). Among high-normal blood pressure group, body mass index, weekly ethanol amounts, weekly physical activity, and dietary fiber except history of quitting smoking were still risk factors of hypertension. Conclusion : 'High-normal blood pressure' is a risk factor for hypertension in Korean middle-aged men, which represents that the vigorous lifestyle modification for persons with 'high-normal blood pressure' is need.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.3
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• pp.313-323
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• 2021

The purpose of this study was to investigate trends in dental sedation of Korean children and adolescents. A retrospective study was conducted on patients under 20 years of age who received dental treatment under sedation using National Health Insurance Service-National Sample Cohort Database from 2002 to 2015. Based on the 1 million standard data, there were 436 cases of dental treatment under sedation in 2002, but 4002 cases in 2015, showing a trend increasing every year. The 3 - 5 year old group accounted for the largest portion (54.2%), while the 6 - 8 year old group increased recently. Nitrous oxide inhalation sedation is the most commonly used, accounting for 45.9% in 2002, but increased to 89.5% in 2015. Combination of nitrous oxide inhalation sedation, chloralhydrate and hydroxyzine was the most common, accounting for 5.7% in 2002, but decreased to 2.9% in 2015. There is a trend to use the sedation method more safely and in a way that reduces side effects.

• Journal of Chest Surgery
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• v.55 no.5
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• pp.378-387
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• 2022

Background: Atrial fibrillation (Afib) is a marker of increased cardiovascular morbidity and mortality. Owing to the increased prevalence of Afib in patients undergoing cardiac surgery, assessing the effect of Afib on postsurgical outcomes is important. We aimed to analyze the effect of preoperative Afib on clinical outcomes in patients undergoing cardiac surgery using a large surgical database. Methods: This retrospective cohort study was based on the national health claims database established by the National Health Insurance Service of the Republic of Korea from 2009 to 2015. Diagnosis and procedure codes were used to identify diseases according to the International Statistical Classification of Diseases, 10th revision. Results: We included 1,037 patients (0.1%) who had undergone cardiac surgery from a randomized 1,000,000-patient cohort, and 15 patients (1.5%) treated with isolated surgical Afib ablation were excluded. Of these 1,022 patients, 412 (39.7%), 303 (29.2%), and 92 (9.0%) underwent coronary artery bypass, heart valve surgery, and Cox-maze surgery, respectively. Preoperative Afib was associated with higher patient mortality (p=0.028), regardless of the surgical procedure. Patients with preoperative Afib (n=190, 18.6%) experienced a higher cumulative risk of overall mortality (hazard ratio [HR], 1.435; 95% confidence interval [CI], 1.263-2.107; p=0.034). Subgroup analysis revealed a reduced risk of overall mortality with Cox-maze surgery in Afib patients (HR, 0.500; 95% CI, 0.266-0.938; p=0.031). Postoperative cerebral ischemia or hemorrhage events were not related to Afib. Conclusion: Preoperative Afib was independently associated with worse long-term postoperative outcomes after cardiac surgery. Concomitant Cox-maze surgery may improve the survival rate.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.4
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• pp.376-383
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• 2021

The aim of this study was to determine the prevalence and incidence and evaluate the current status of dental treatment of Amelogenesis imperfecta (AI) and Dentinogenesis imperfecta (DI) in South Korea. The data was based on National Health Insurance Service (NHIS)-National Sample Cohort Database (2002 - 2015) and Jeonbuk National University (JBNU) Dental Hospital (2011 - 2020). The NHIS data analysis showed prevalence of AI and DI were 11.6 and 2.4 per 100,000 people, respectively. The annual incidence of AI and DI for 2013 - 2015 were 2.2 and 0.5 per 100,000. There were no statistically significant differences regarding the number of visits, the reimbursable cost among AI, DI patients and others. In the patient analysis of the JBNU dental hospital, proportion of the reimbursable and non-reimbursable cost for AI patients were 12.1% and 87.9%, while DI patients accounted for 18.6% and 81.4%.

• Health Policy and Management
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• v.27 no.2
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• pp.128-138
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• 2017

Background: The purpose of this study is to analyze the effects of differential coinsurance policy on prescription drug coverage of outpatients by types of medical institutions. Methods: In this study, we used a sample cohort database of the National Health Insurance Service and frequency analysis and marginal logistic regression model using generalized estimating equation were used for statistical analysis. Results: The summary on the major research is followed. First, about 16% of patients who used only tertiary or general hospital due to 52 ambulatory care sensitive conditions before policy implementation moved to hospitals and clinics. However, about 57% of them still use tertiary or general hospital. Second, the factors influencing the utilization of hospitals and clinics after the implementation of the policy were gender, age, and income level. As a result, the policy is effective to reduce the medical use of outpatient mental patients in tertiary or general hospital, but the effect is not significant. Conclusion: Therefore, in order to achieve the purpose of the policy for establishing the health care delivery system, it is necessary to adjust the co-payment so as to feel the burden on the co-payment when the outpatient for 52 ambulatory care sensitive conditions is used at the tertiary or general hospital.

• Korean Journal of Community Nutrition
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• v.26 no.3
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• pp.211-227
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• 2021

Objectives: We aimed to examine the association between the relative preference for vegetables and meat and cancer incidence, in a population-based retrospective cohort in Korea. Methods: We included 10,148,131 participants (5,794,124 men; 4,354,007 women) who underwent national health screening between 2004 and 2005 from the National Health Information Database of the National Health Insurance Service (NHIS-NHID). Participants were asked whether they preferred consuming 1) vegetables more often, 2) both vegetables and meat or 3) meat more often. Participants were followed up to Dec. 31, 2017. All cancer and eighteen common cancer cases were identified through the code from the International Classification of Diseases, 10th revision. We estimated sex-specific relative risks and 95% confidence intervals, adjusting for age, body mass index, alcohol consumption, smoking, physical activity, and income level. Results: During an average follow-up of 12.4 years, 714,170 cancer cases were documented. In men, consuming meat more often was associated with lower risk of esophageal, liver, and stomach cancers, but higher risk of lung and kidney cancers. Consuming both vegetables and meat was associated with higher risk of prostate cancer, but with lower risk of esophageal, liver, and stomach cancers in men. In women, consuming meat more often was associated with a higher risk of colorectal cancer and breast, endometrial, and cervical cancers diagnosed before the age of 50. Consuming both vegetables and meat was associated with lower risk of liver cancer in women. Conclusions: Our study suggests a potential link between vegetable and meat intake and cancer incidence in the Korean population. Further investigation on the association between the intake of specific types of vegetables and meat and cancer risk in Korean prospective cohort studies is needed.