• Journal of Korean Neurosurgical Society
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• v.63 no.6
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• pp.730-737
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• 2020

Objective : Spinal degeneration is a progressive disease, worsening over time. Lumbar degenerative disease (LDD) is a major spinal disease in elderly patients. Surgical treatment is considered for medically intractable patients with LDD and reoperation after primary surgery is not uncommon. The surgical outcome is occasionally unpredictable because of comorbidities. In the present study, the relationship between comorbidities and the incidence of reoperation for LDD over time was determined. Methods : The claims data of the health insurance national database were used to identify a cohort of patients who underwent spinal surgery for LDD in 2009. The patients were followed up until 2016. Medical comorbidity was assessed according to the Charlson comorbidity index (CCI). Cox proportional hazard regression modeling was used to identify significant differences in sex, surgery, age, causative disease, and comorbidity. Results : The study cohort included 78241 patients; 10328 patients (13.2%) underwent reoperation during the observation period. The reoperation rate was statistically higher (p<0.01) in males, patients 55-74 years and 65-74 years of age, and patients with decompression or discectomy. Significant association was found between increasing reoperation rate and CCI score (p<0.01). Based on multivariate analysis of comorbidities, the significantly higher reoperation rates were observed in patients with peripheral vascular disease, pulmonary lung disease, peptic ulcer, diabetes, and diabetes complications (p<0.01). Conclusion : The study results indicate the reoperation rate for LDD is associated with patient comorbidities. The comorbidities identified in this study could be helpful in future LDD studies.

• 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.

• The Journal of Korean Medicine
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• v.40 no.3
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• pp.1-20
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• 2019

Objectives: This study aims to investigate the effects of Korean Medicine Hospital Utilization (KMHU) on major adverse cardiovascular events (MACE), myocardial infarction (MI), stroke, and death in hypertensive patients taking antihypertensives. Methods: Using the Korean National Health Insurance Service-National Sample Cohort database, this study identified and diagnosed 68,457 hypertensive patients taking antihypertensives between 2003 and 2006. They were divided into KMHU and non-KMHU groups. The follow-up period ended with the diagnosis of myocardial infarction, stroke, or death. After propensity score matching (PSM), there were 18,242 patients each in the non-KMHU and KMHU groups. We calculated the incidence rate, hazard ratio (HR), and 95% confidence interval (CI) for MACE, myocardial infarction, stroke, and death in patients with hypertension using a stratified Cox proportional hazard model. In addition, secondary outcome analyses for stroke and cardiovascular mortality were performed. Results: After PSM, the HRs for MACE (HR: 0.84, 95% CI: 0.81-0.87), all-cause mortality (HR: 0.75, 95% CI: 0.72-0.79), and myocardial infarction (HR: 0.90, 95% CI: 0.83-0.97) were significantly lower in the KMHU group than in the non-KMHU group. Moreover, the HRs for stroke-related mortality, haemorrhage and ischaemic stroke-related mortality, and ischaemic heart disease-related and circulatory system disease-related mortality were significantly lower in the KMHU group than in the non-KMHU group. Conclusions: On long-term follow-up observation, this study supported the effect of KMHU for managing hypertension and reducing the burden of cardiovascular diseases.

• Journal of Society of Preventive Korean Medicine
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• v.25 no.3
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• pp.25-37
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• 2021

Objectives : To investigate the effectiveness of Korean Medicine services use on the all-cause mortality and incidence of Parkinson's disease(PD) in elderly patients with chronic disease based on the National Health Insurance Service Corhort Database (elderly), called as the NHIS-senior. Methods : This study was a retrospective cohort analysis conducted using the NHIS-senior. Patients with chronic diseases over 65 years old who were not diagnosed PD during 2007-2009 were identified. The case group was defined as patients who used both Korean Medicine and Western Medicine services and the control group consisted of patients who used Western Medicine service only. The all-cause mortality and incidence of PD was analyzed using the Cox proportional hazard model after a propensity score matching(PSM) with a 1:1 ratio. Results : After PSM, the cohort included 47,546 subjects (23,773 in the case group, 23,773 in the control group). Sex, age, comorbidity, severity of disability, and neurology medical service utilization were adjusted in both groups. The mortality was 0.668 times (95% C.I.: 0.646-0.690) lower in the case group than the control group, which was statistically significant (p<0.001). The incidence of PD was 1.051 times (95% C.I.: 0.962-1.148) higher in the case group than the control group, which was not statistically significant(p=0.272). Conclusion : It was not obvious that the use of both Korean Medicine service and Western Medicine services for prevention of PD is benefitial than using only Western Medicine. But it would be possible that using both Korean Medicine and Western Medicine services decreases the mortality than using Western Medicine alone.

• 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.52 no.3
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• pp.188-194
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• 2019

Objectives: Outbreaks of scarlet fever in Mexico in 1999, Hong Kong and mainland China in 2011, and England in 2014-2016 have received global attention, and the number of notified cases in Korean children, including in Jeju Province, has also increased since 2010. To identify relevant hypotheses regarding this emerging outbreak, an age-period-cohort (APC) analysis of scarlet fever incidence was conducted among children in Jeju Province, Korea. Methods: This study analyzed data from the nationwide insurance claims database administered by the Korean National Health Insurance Service. The inclusion criteria were children aged ${\leq}14years$ residing in Jeju Province, Korea who received any form of healthcare for scarlet fever from 2002 to 2016. The age and year variables were categorized into 5 groups, respectively. After calculating the crude incidence rate (CIR) for age and calendar year groups, the intrinsic estimator (IE) method was applied to conduct the APC analysis. Results: In total, 2345 cases were identified from 2002 to 2016. Scarlet fever was most common in the 0-2 age group, and boys presented more cases than girls. Since the CIR decreased with age between 2002 and 2016, the age and period effect decreased in all observed years. The IE coefficients suggesting a cohort effect shifted from negative to positive in 2009. Conclusions: The results suggest that the recent outbreak of scarlet fever among children in Jeju Province might be explained through the cohort effect. As children born after 2009 showed a higher risk of scarlet fever, further descriptive epidemiological studies are needed.

• Journal of Preventive Medicine and Public Health
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• v.56 no.4
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• pp.312-318
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• 2023

Objectives: We reviewed the operational definitions of colorectal cancer (CRC) from studies using the Korean National Health Insurance Service (NHIS) and compared CRC incidence derived from the commonly used operational definitions in the literature with the statistics reported by the Korea Central Cancer Registry (KCCR). Methods: We searched the MEDLINE and KoreaMed databases to identify studies containing operational definitions of CRC, published until January 15, 2021. All pertinent data concerning the study period, the utilized database, and the outcome variable were extracted. Within the NHIS-National Sample Cohort, age-standardized incidence rates (ASRs) of CRC were calculated for each operational definition found in the literature between 2005 and 2019. These rates were then compared with ASRs from the KCCR. Results: From the 62 eligible studies, 9 operational definitions for CRC were identified. The most commonly used operational definition was "C18-C20" (n=20), followed by "C18-C20 with claim code for treatment" (n=3) and "C18-C20 with V193 (code for registered cancer patients' payment deduction)" (n=3). The ASRs reported using these operational definitions were lower than the ASRs from KCCR, except for "C18-C20 used as the main diagnosis." The smallest difference in ASRs was observed for "C18-C20," followed by "C18-C20 with V193," and "C18-C20 with claim code for hospitalization or code for treatment." Conclusions: In defining CRC patients utilizing the NHIS database, the ASR derived through the operational definition of "C18-C20 as the main diagnosis" was comparable to the ASR from the KCCR. Depending on the study hypothesis, operational definitions using treatment codes may be utilized.

• The Korean Journal of Health Service Management
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• v.11 no.3
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• pp.65-78
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• 2017

Objectives : Obesity is a worldwide health concern due to an increasing obese population. This study proposed to analyze the differences in medical costs and care utilization between obese and normal group using propensity score matching. Methods : Data were collected from the sample cohort database by the Korea National Health Insurance Corporation. Propensity score matching(PSM) was applied to control selection bias, and factors affecting obesity were used as covariates in PSM. Results : The results showed higher medical costs and care utilization in the obese group than the normal group. According to gender and medical type, there were differences in the relationships between obesity and medical charges and utilization. In particular, the differences in the female population were larger in both outpatients and inpatients than the male population. Conclusions : It is important to manage obesity, because obesity has a negative effect on national health insurance costs. These findings suggest directions for future research.

• Therapeutic Science for Rehabilitation
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• v.12 no.1
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• pp.51-63
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• 2023

Objective : This study aimed to analyze the association between lifestyle and medical expenses of older adults with mental illness using claims data. Methods : We conducted secondary data analysis using the older adult cohort database provided by the Korea National Health Insurance Service. The lifestyle and medical expense variables were extracted from the cohort database. We used a generalized linear model to examine the association between lifestyle and medical expenses. Results : In total, 32,853 records were extracted. The results showed that smokers had medical expenses (estimate = -218,255, p = .037). As the number of days of walking increased, medical expenses significantly decreased (estimate = -58,843, p < .0001). Furthermore, as the number of days of drinking decreased, medical expenses increased (estimate = 692,289, p < .0001). Conclusion : This study analyzed the estimates of medical expenses according to lifestyle among older adults with mental illness. Smoking and exercise were negatively associated with medical expenses. These results suggest the importance of a healthy lifestyle for older adults with mental illness. In addition, this study can be used as clinical evidence for lifestyle management programs to improve physical and mental health.

• Journal of muscle and joint health
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• v.29 no.1
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• pp.41-49
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• 2022

Purpose: The purpose of this study was to assess the influence of nurses staffing level on patient health outcomes in intensive care units (ICUs) in Korea. Methods: The study was retrospective in nature. Information on patients and their outcomes, as well as nurse cohort data, were obtained from Korea's National Health Insurance Service Database. The observation period was from January 1, 2008 to December 31, 2018, and data for 2,964,991 patients were analyzed. Independent variables included patient' age and sex and hospital type, intensivist, and nurses staffing level. Results: The mortality rate in ICUs was significantly higher at tertiary hospitals with a level 3~4 (HR, 1.21; 95% confidence interval, 1.19~1.22) or level 5~9 nurse staffing (HR, 1.31; 95% confidence interval, 1.27~1.34) compare to that of tertiary hospitals with a 1~2 level. 28-day mortality rate was also higher at general hospitals with a level 3~4 (HR, 1.13; 95% confidence interval, 1.12~1.14), level 5~6 (HR. 1.34; 95% confidence interval, 1.32~1.36), level 7~9 nurse staffing (HR, 1.38; 95% confidence interval, 1.38~1.42), using level 1~2 as reference. Conclusion: Nurses staffing level is a key determinant of healthcare-associated mortality in critically ICUs patients. Policies to achieve adequate nurse staffing levels are therefore required to enhance patient outcomes.