• Journal of Society of Preventive Korean Medicine
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• v.28 no.1
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• pp.69-87
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• 2024

Objectives : This study is to investigate the current National Health Insurance Database cohort studies related to complications of Parkinson's Disease (PD) and suggest the design of Korean medical epidemiological studies of PD. Methods : Nationwide longitudinal studies of PD patients in South Korea were collected through Pubmed and the Korea Citation Index (KCI). We selected cohort studies that used the National Health Insurance Database in Korea and targeted Parkinson's disease patients. Studies published before February 2024 were categorized according to study designs. We examined variables and covariates, enroll dates and matching methods. Results : Of a total of 536 studies, 18 studies met the inclusion criteria. All studies used the National Health Insurance (NHI) Research Database and among them, 5 used sample data and one senior database. Studies can be classified into two types. 11 cohort studies were comparing PD patients and non-PD patients. Another type was 4 PD patients cohort studies. Most studies used two diagnostic codes (G20 and V124) for inclusion criteria. Enroll periods were from 2002 to 2017, and follow-up periods were from 7 to 14 years. 16 studies considered age and sex as covariates. 15 studies used the propensity score matching method to increase the level of causality. There was only one study related to the Korean medical treatment. Conclusion : In future cohort studies on Korean medical treatment, more attempts should be made to reveal the effect of the treatments on PD patients by defining inclusion criteria for patient groups, covariates, exposure variables, and assessment indicators more operatively.

• The Korean Journal of Applied Statistics
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• v.30 no.1
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• pp.13-24
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• 2017

The Sample Cohort DB supplied by the National Health Insurance Service is a valuable resource for statistical studies as well as for health and medical studies. It takes significant time and effort to extract data from this Cohort DB having a large size. As such, we introduce a database system, conveniently called the National Health Insurance Service Cohort DB Extract Tool (NICE Tool), which supports several useful operations for effectively and efficiently managing the Cohort DB. For example, researchers can extract variables and cases related with study by simply clicking a computer mouse without any prior knowledge regarding SAS DATA step or SQL. We expect that NICE Tool will facilitate the faster extraction of data and eventually lead to the active use of the Cohort DB for research purposes.

• Korean Journal of Clinical Pharmacy
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• v.29 no.3
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• pp.147-155
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• 2019

Objectives: The purpose of this study was to investigate the association between fracture risk and proton pump inhibitor (PPI) use to establish evidence for defining high-risk groups of fracture among PPI users. Methods: A case-control study was performed using the National Health Insurance Sample Cohort Database from January 2002 to December 2013. The cases included all incidences of major fractures identified from January 2011 to December 2013, and up to four controls were matched to each case by age, gender, osteoporosis, and Charlson comorbidity index. Conditional logistic regression was used to calculate the adjusted odds ratio (aOR) and associated 95% confidence interval (CI). Results: Overall, 14,295 cases were identified, and 63,435 controls were matched to the cases. The aOR of fractures related to the use of PPIs was 1.06 (95% CI: 1.01-1.11). There was a statistically significant association between fracture and PPI use within 3 months of the last dose, and a trend of increasing fracture risk with increasing cumulative PPI dose. The risk of fracture was significantly higher in patients who took PPIs for more than 1 year during the 2-year observation period. Conclusion: Patients who have been using PPIs for more than 1 year should be warned about the risk of fracture during or at least 3 months after discontinuing the PPI.

• Archives of Craniofacial Surgery
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• v.22 no.5
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• pp.254-259
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• 2021

Background: Prophylactic antibiotics are commonly used in craniofacial surgeries. Despite the low risk of surgical site infection after nasal surgery, a lack of consensus regarding the use of antibiotic prophylaxis in the closed reduction of nasal bone fractures has led to inappropriate prescribing patterns. Through this study, we aimed to investigate the status of prophylactic antibiotic use in closed reductions of nasal bone fractures in Korea. Methods: This retrospective cohort study was conducted using data from the National Health Insurance Service-National Sample Cohort of Korea from 2005 to 2015. We analyzed the medical records of patients who underwent closed reduction of nasal bone fractures. The sex, age, region of residence, comorbidities, and socioeconomic variables of the patients were collected from the database. Factors that affect the prescription of perioperative antibiotics were evaluated using multivariate logistic regression analysis. Results: A total of 3,678 patients (mean±standard deviation of age, 28.7±14.9 years; 2,850 men [77.5%]; 828 women [22.5%]) were included in this study. The rate of antibiotic prescription during the perioperative period was 51.4%. Approximately 68.8% of prescriptions were written for patients who had received general anesthesia. The odds of perioperative prophylactic antibiotic use were significantly higher in patients who received general anesthesia than who received local anesthesia (odds ratio, 1.59). No difference was found in terms of patient age and physician specialty. Second-generation cephalosporins were the most commonly prescribed antibiotic (45.3%), followed by third- and first-generation cephalosporins (20.3% and 18.8%, respectively). In contrast, lincomycin derivatives and aminoglycosides were not prescribed. Conclusion: The findings of this study showed that there was a wide variety of perioperative antibiotic prescription patterns used in nasal bone surgeries. Evidence-based guidance regarding the prescribing of antimicrobial agents for the closed reduction of nasal bone fractures should be considered in future research.

• The Korean Journal of Applied Statistics
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• v.30 no.3
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• pp.475-486
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• 2017

This paper estimates the health life expectancies for Korean people based on a sample cohort database collected through objective measurements by the National Health Insurance Service. Health life expectancy is estimated using the single-state approach of Sullivan (1971). The 9-order correction factor method of Greville (1945) and Brass-logit model of Brass (1971) are also adopted for unobserved or incompletely observed age-specific morbidity and mortality. Based on the mortality and morbidity estimated from sample cohort DB, men and women in Korea are expected to live a 'healthy life' for 61 and 60 years in 2013, respectively, whereas life expectancies of men and women are 80 and 87, respectively. We also estimate certain disease-free life expectancies for each of genders, income levels, and types of insurance from 2003 to 2013 in Korea. We found that there exists an inequality of healthy life expectancy in Korea for different genders, income levels, and types of insurance.

• Journal of Periodontal and Implant Science
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• v.47 no.2
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• pp.96-105
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• 2017

Purpose: The National Health Insurance Service-National Sample Cohort and medical checkup data from 2002 to 2013 were used to evaluate the association between periodontal surgery for the treatment of periodontitis (PSTP) and vasculogenic erectile dysfunction (VED). Methods: Bivariate and multivariate logistic regression analyses were applied to a longitudinal retrospective database to assess the association between PSTP and VED while adjusting for the potential confounding effects of sociodemographic factors (age, household income, insurance status, health status, residence area, and smoking status) and comorbidities (diabetes mellitus, angina pectoris, cerebral infarction, and myocardial infarction). Results: Among the 7,148 PSTP within the 268,296 recruited subjects, the overall prevalence of VED in PSTP was 1.43% (n=102). The bivariate analysis showed that VED was significantly related to PSTP (odds ratio [OR], 1.99; 95% confidence interval [CI], 1.38-2.06; P<0.001), and this was confirmed in the multivariate analysis after adjusting for sociodemographic factors and comorbidities (OR, 1.29; 95% CI, 1.06-1.58; P=0.002). Conclusions: Subjects with a history of periodontal flap surgery had a significantly higher risk of VED, after adjusting for potential confounding factors. Further studies are required to identify the key mechanisms underlying the association between severe periodontal disease and VED.

• Journal of Periodontal and Implant Science
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• v.47 no.5
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• pp.264-272
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• 2017

Purpose: This study evaluated trends in tooth extraction due to acute and chronic periodontal disease (PD) using data from the National Health Insurance Service-National Sample Cohort for 2002-2013. Methods: A random sample of 1,025,340 individuals was selected as a representative sample of the population, and a database (DB) of diagnostic and prescription codes was followed up for 12 years. We used multivariate logistic regression analysis to assess the incidence of total extraction (TE), extraction due to periodontal disease (EPD), and immediate extraction due to periodontal disease (IEPD) according to sociodemographic factors (sex, age, household income, health status, and area of residence). Results: The incidence of tooth extraction was found to be increasing, and at a higher rate for TE in PD patients. In 2002, 50.6% of cases of TE were caused by PD, and this increased to 70.8% in 2013, while the number of cases of IEPD increased from 42.8% to 54.9% over the same period. The incidence rates of extraction due to acute and chronic PD increased monotonically. We found that the incidence rates of TE, EPD, and IEPD were all 2-fold higher among patients with high income levels and those who were not beneficiaries of health insurance. Conclusions: The rates of TE, EPD, and IEPD have been steadily increasing despite dental healthcare policies to expand public health insurance coverage, increasing the accessibility of dental clinics. Moreover, the effects of these policies were found to vary with both income and education levels. Consistent patient follow-up is required to observe changes in trends regarding tooth extraction according to changes in dental healthcare policies, and meticulous studies of such changes will ensure optimal policy reviews and revisions.

• Journal of Preventive Medicine and Public Health
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• v.49 no.3
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• pp.143-152
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• 2016

Objectives: Metabolic syndrome is a cluster of risk factors for type 2 diabetes mellitus and cardiovascular disease. Associations between metabolic syndrome and several types of cancer have recently been documented. Methods: We analyzed the sample cohort data from the Korean National Health Insurance Service from 2002, with a follow-up period extending to 2013. The cohort data included 99 565 individuals who participated in the health examination program and whose data were therefore present in the cohort database. The metabolic risk profile of each participant was assessed based on obesity, high serum glucose and total cholesterol levels, and high blood pressure. The occurrence of cancer was identified using Korean National Health Insurance claims data. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models, adjusting for age group, smoking status, alcohol intake, and regular exercise. Results: A total of 5937 cases of cancer occurred during a mean follow-up period of 10.4 years. In men with a high-risk metabolic profile, the risk of colon cancer was elevated (HR, 1.40; 95% CI, 1.14 to 1.71). In women, a high-risk metabolic profile was associated with a significantly increased risk of gallbladder and biliary tract cancer (HR, 2.05; 95% CI, 1.24 to 3.42). Non-significantly increased risks were observed in men for pharynx, larynx, rectum, and kidney cancer, and in women for colon, liver, breast, and ovarian cancer. Conclusions: The findings of this study support the previously suggested association between metabolic syndrome and the risk of several cancers. A high-risk metabolic profile may be an important risk factor for colon cancer in Korean men and gallbladder and biliary tract cancer in Korean women.

• Journal of Preventive Medicine and Public Health
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• v.53 no.5
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• pp.313-322
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• 2020

Objectives: This study was conducted to determine the incidence and risk factors of myocardial infarction (MI) and stroke in farmers compared to the general population and to establish 5-year prediction models. Methods: The farmer cohort and the control cohort were generated using the customized database of the National Health Insurance Service of Korea database and the National Sample Cohort, respectively. The participants were followed from the day of the index general health examination until the events of MI, stroke, or death (up to 5 years). Results: In total, 734 744 participants from the farmer cohort and 238 311 from the control cohort aged between 40 and 70 were included. The age-adjusted incidence of MI was 0.766 and 0.585 per 1000 person-years in the farmer and control cohorts, respectively. That of stroke was 0.559 and 0.321 per 1000 person-years in both cohorts, respectively. In farmers, the risk factors for MI included male sex, age, personal history of hypertension, diabetes, current smoking, creatinine, metabolic syndrome components (blood pressure, triglycerides, and high-density lipoprotein cholesterol). Those for stroke included male sex, age, personal history of hypertension, diabetes, current smoking, high γ-glutamyl transferase, and metabolic syndrome components (blood pressure, triglycerides, and high-density lipoprotein cholesterol). The prediction model showed an area under the receiver operating characteristic curve of 0.735 and 0.760 for MI and stroke, respectively, in the farmer cohort. Conclusions: Farmers had a higher age-adjusted incidence of MI and stroke. They also showed distinct patterns in cardiovascular risk factors compared to the general population.

• Health Policy and Management
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• v.30 no.4
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• pp.522-530
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• 2020

Background: In 2008, Korea implemented a new type of social insurance known as "long-term care insurance". We examined the association between ownership of long-term care facilities and the incidence of pressure ulcers after the implementation of "long-term care insurance". This study is a population-based retrospective cohort study from 2006 to 2013. Methods: We used medical claims data from the Korean National Health Insurance Corporate Elderly Cohort Database from 2006 to 2013. These data comprise a nationally representative sample. To avoid confounders, only patients admitted to one long-term care facility and who stayed for >70% of the follow-up time were included; as a result, 3,107 individuals were enrolled. The main independent variable was the operating entity of the long-term care facility (local government, corporate bodies, and private for-profit owners), and the dependent variable was the 1-year incidence of pressure-ulcers. Survival analysis (Cox proportional hazard model) was used as an analysis method. Results: Compared to patients admitted to local government long-term care facilities, patients admitted to private long-term care facilities had a significantly higher 1-year risk of pressure ulcers (hazard ratio [HR], 1.94; 95% confidence interval [CI], 1.29-2.91); the risk was especially high among patients who were cognitively dependent (HR, 2.34; 95% CI, 1.25-4.37). Conclusion: Patients admitted to private for-profit long-term care facilities were more likely to have pressure ulcers compared to those in local government and corporate body long-term care facilities. Appropriate assessment tools and publicly available information, as well as more restricted legal requirements, are needed to improve the care quality and outcomes of patients in long-term care facilities.