Risk factors for middle ear cholesteatoma surgery based on Korean population data.

BACKGROUND: Studies of risk factors for middle ear cholesteatoma surgery using population-based data are lacking. OBJECTIVES: To investigate the risk factors for cholesteatoma surgery in adults based on population data from Korea. MATERIALS AND METHODS: For this retrospective study, we used Korean National Health Insurance Service National Sample Cohort data. Patients who were 20 years or older and underwent mastoidectomy from 2006 through 2015 under the diagnostic codes of cholesteatoma were defined as patients with middle ear cholesteatoma surgery. The control group was comprised of the remaining database sample in 2006. Sociodemographic factors in 2006 and histories of medical diseases, allergic diseases, and chronic sinusitis from 2003 through 2005 were compared between cholesteatoma surgery and control groups. RESULTS: A total of 459 patients underwent cholesteatoma surgery. In multivariate Cox regression analysis, age 40-59 years and residence in metropolitan cities and small- and medium-sized cities and counties were significant risk factors for cholesteatoma surgery whereas allergic rhinitis, asthma, atopic dermatitis, and chronic sinusitis were not significant risk factors for middle ear cholesteatoma surgery. CONCLUSIONS AND SIGNIFICANCE: The present study found no evidence of associations between allergic diseases or chronic sinusitis and cholesteatoma surgery in adults.

Seasonal variation in peripheral vestibular disorders based on Korean population data.

Objectives: Comprehensive studies in which the seasonal variation in peripheral vestibular disorders was evaluated using data from an entire population are insufficient. The seasonal variation in peripheral vestibular disorders based on data from the entire Korean population was investigated in the present study. Methods: Retrospective data from the National Health Insurance Service of Korea from 2008 to 2020 was analyzed. Benign paroxysmal positional vertigo (BPPV), vestibular neuritis (VN), and Meniere's disease (MD) were defined based on diagnostic, treatment, or audiovestibular test codes. The seasonal incidence for each peripheral vestibular disorder was calculated among all study subjects. Results: For the entire study cohort, the incidence of BPPV was significantly higher in spring (odds ratio [OR] = 1.031, 95% confidence interval [CI] = 1.026-1.037), autumn (OR = 1.024, 95% CI = 1.019-1.029), and winter (OR = 1.051, 95% CI = 1.046-1.056) than in summer. The incidence of VN was significantly lower in winter (OR = 0.917, 95% CI = 0.907-0.927) than in summer. The incidence of MD was significantly higher in spring (OR = 1.027, 95% CI = 1.015-1.039) and autumn (OR = 1.029, 95% CI = 1.017-1.041) and significantly lower in winter (OR = 0.919, 95% CI = 0.908-0.931) than in summer. Differences were also observed in seasonal variation based on sex and age. Conclusions: Significant seasonal variation occurred in peripheral vestibular disorders including BPPV, VN, and MD based on the entire Korean population data. Furthermore, seasonal variation showed differences based on sex and age. Level of Evidence: 4.

Estimation of the Three Phases by Direct Cost of Care for Non-surviving Patients with Cancer: A National Population-based Patient-level Study.

Background: Determining the cost structure of medical care from diagnosis to the death of patients with cancer is crucial for establishing budgets to support patients with cancer. The breakdown of the cost estimation in distinct phases of survival is essential for optimizing the allocation of limited funds. Therefore, this study aims to examine the patterns of direct medical costs of cancer care associated with seven major cancer types and estimate cost thresholds to distinguish each phase based on the incurred cost. Methods: In this nationwide, population-based study, we used claims data from the National Health Insurance Service, Korea. Patients newly diagnosed with cancer since 2006 and who died in 2016-2017 were enrolled, and their use of medical services during cancer survival from at least 6 months up to 12 years was observed. The monthly cost exhibited a non-linear function with two unknown thresholds resembling a U-shape; therefore, we fitted three linear segment models. Individual costs were assessed by dividing the survival time into the initial, continuing, and terminal phases by estimated thresholds, and the average medical cost for each phase was calculated. Results: Based on survival durations of 12 years or less, the initial phase occurred within 1.1-4.8 months after diagnosis, while the terminal phase was observed in 1.4-4.7 months before death. The length of these two phases increased with the increased survival time of the patients. Medical costs in these phases ranged from $4067-7431 and $3127-6114 (US dollars), respectively, regardless of the variations in survival time. However, the average costs in the continuing phase were higher for patients with a short survival time. Conclusions: This study highlights the cost dynamics in cancer care through a breakdown of the phases of survival. It suggests that through a more refined definition of the initial and terminal phases, the average cost in these stages increases, indicating the significant implications of the findings for resource allocation and tailored financial support strategies for patients with cancer with varying prognoses.

Perinatal and childhood outcomes of children born to female cancer survivors in South Korea.

Despite the increasing number of female cancer survivors, uncertainty remains regarding potential adverse health outcomes for their offspring. Comprehensive population-based studies would be invaluable for female cancer survivors in making decisions about their future. This study uses the National Health Information Database to investigate perinatal and long-term outcomes of offspring born to mothers with a history of cancer. In a South Korean cohort of 95,264 women aged 15-40 diagnosed with cancer between 2007 and 2010, we evaluated the outcomes of 15,221 children born to 11,092, cancer survivors. We selected 147,727 women without a history of cancer and 201,444 children as a control group. Our study found that children of female cancer survivors have a significantly higher odds ratio of primary outcomes including preterm birth, low birth weight, neonatal intensive care unit admission, and death. While there was no difference in the rate of death within 1 year of birth between the two groups, the total death rate during the follow-up period was significantly higher in children born to mothers with cancer. After adjusting for gestational age and birth weight, there was no statistically significant increased hazard ratio of secondary outcomes including cancer, chromosomal abnormalities, cerebral palsy, delayed development, epilepsy, language disorder, or hearing impairment.

Reference Standard for Digital Infrared Thermography of the Surface Temperature of the Lower Limbs.

Digital infrared thermographic imaging (DITI) is a supplementary diagnostic technique to visualize the surface temperature of the human body. However, there is currently no reference standard for the lower limbs for accurate diagnosis. In this study, we performed DITI on the lower limbs of 905 healthy Korean volunteers (411 males and 494 females aged between 20 and 69 years) to obtain reference standard data. Thermography was conducted on the front, back, lateral sides, and sole area, and 188 regions of interest (ROIs) were analyzed. Additionally, subgroup analysis was conducted according to the proximity of ROIs, sex, and age groups. The mean temperatures of ROIs ranged from 24.60 ± 5.06 to 28.75 ± 5.76 °C and the absolute value of the temperature difference between both sides reached up to 1.06 ± 2.75 °C. According to subgroup analysis, the sole area had a significantly lower temperature than any other areas, men had higher temperatures than women, and the elderly had higher temperatures than the young adults except for the 20s age group (p < 0.001, respectively). This result could be used as a foundation for the establishment of a reference standard for DITI. Practical patient DITI can be accurately interpreted using these data, and it can serve as a basis for further scientific research.

Incidence of peripheral vestibular disorders based on population data of South Korea.

BACKGROUND: There have been no comprehensive studies on the incidence of peripheral vestibular disorders based on population-based data for a long-term period. OBJECTIVE: We investigated the incidence of peripheral vestibular disorders using population-based data representing the whole population of South Korea. METHODS: This study used the National Health Insurance Service data in Korea from 2008 to 2020. Peripheral vestibular disorders such as benign paroxysmal positional vertigo (BPPV), vestibular neuritis (VN), and Meniere's disease (MD) were defined with diagnostic, treatment, or audiovestibular test codes. The annual incidence in total and according to sex, age, and residence was analyzed. RESULTS: The annual incidence of BPPV, VN, and MD per 100,000 was 51.4, 22.7, and 12.4 in 2008 and 181.1, 62.9, and 50.5 in 2020, respectively. The incidence of each was significantly different by sex (p < 0.001), age (p < 0.001), and residence (p < 0.001), with the highest value in female, people aged 60 years or older, and people who resided in metropolitan cities. CONCLUSIONS: The annual incidence of BPPV, VN, and MD had increasing trends from 2008 through 2020 in South Korea, and all were significantly higher in female, people aged 60 years or older, and people who resided in metropolitan cities.

Long-term outcomes of preterm infants in the first 6 years of life: a nationwide population-based study in Korea.

This study examined the relationship between gestational age and long-term outcomes up to 6 years of age using population-based big data from the National Health Insurance Service in Korea. This retrospective observational cohort study used data from the National Health Information Database (2011-2017). All children born in Korea during 2011 (January 1-December 31) were eligible and were followed up until 2017. Gestational age groups were divided into extremely preterm (< 28 weeks), very preterm (28-31 weeks), moderate-to-late preterm (32-36 weeks), and full-term (37-41 weeks). The survival rate, neurodevelopmental diseases, hearing or visual impairment, and respiratory morbidities were compared for each gestational age group. In total, 370,301 children were included in the analysis. The total survival rate increased with increasing gestational age. Furthermore, the risk of neurodevelopmental diseases (i.e., epilepsy, cerebral palsy, delayed development, mental retardation, language disorder, developmental coordination disorder, autism spectrum disorder), hearing or visual impairment, and asthma-related inhaler prescription increased with decreasing gestational age, despite adjustment for covariates. CONCLUSION: Lower gestational age was associated with an increase in a wide spectrum of adverse neurodevelopmental and respiratory outcomes in the first 6 years of life. Although morbidities were highest at the earliest gestational ages, moderate-to-late preterm children were significantly associated with increased adverse outcomes compared with full-term children. Our findings prove this under-recognized group's long-term follow-up and policy support. WHAT IS KNOWN: • Infants born preterm are at high risk for neurodevelopmental and various medical health problems. • Nationwide research on long-term outcomes for moderate-to-late preterm birth is sparse. WHAT IS NEW: • In this nationwide cohort study, lower gestational age at birth was inversely associated with increased adverse neurodevelopmental and respiratory outcomes in the first 6 years of life. • Long-term follow-up and policy support are required for moderate-to-late preterm children who are at risk of increased adverse outcomes compared with full-term births.

Anemia Is a Risk Factor for the Development of Ischemic Stroke and Post-Stroke Mortality.

BACKGROUND: anemia is known to be a risk factor for developing ischemic stroke in long-term follow-up studies, and it is also known to increase the risk of death in ischemic stroke patients. We aimed to determine the association of anemia with the risk of ischemic stroke and the risk of death after ischemic stroke. METHODS: The study included patients from National Health Insurance Service cohort, from January 2005 to December 2015. Anemia patients were defined as those with confirmed diagnostic codes and related medications in the sample cohort, and patients under the age of 18 were excluded. To perform a comparative analysis with the control group, twice as many patients were extracted by propensity score matching. The effects of anemia on the development of ischemic stroke were analyzed. RESULTS: A total of 58,699 patients were newly diagnosed with anemia during the study period. In anemia group, the rate of ischemic stroke occurring within 1 year was 0.550%, and the rate was 0.272% in the control group. The odds ratio of anemia related to ischemic stroke was 1.602 (95% confidence intervals (CI) 1.363-1.883). During the follow-up period, 175 out of 309 (56.6%) died in anemia group, and 130 out of 314 (41.4%) died in control group. The anemia group showed a higher risk of death than the control group (Hazard ratio 1.509, 95% CI 1.197-1.902). CONCLUSION: Analysis of the nationwide health insurance data revealed that anemia is one of the risk factors for the development of ischemic stroke, and also an independent prognostic factor affecting post-stroke mortality.

Neonatal and maternal risk factors for hearing loss in children based on population-based data of Korea.

OBJECTIVES: We identified the neonatal and maternal risk factors for hearing loss (HL) in children using National Health Insurance Service data of Korea. METHODS: We retrospectively analyzed data from the National Health Insurance Service. Infants born from 2007 to 2013 were tracked to 2015. Those diagnosed with hearing disabilities or who underwent cochlear implant surgery were included in the hearing disability group. We compared the incidence of any diagnosed disability other than a hearing disability; any maternal disability at delivery; maternal age at delivery; prenatal and neonatal Toxoplasma, syphilis, rubella, cytomegalovirus, and herpes simplex infections; craniofacial anomaly; low birth weight, hyperbilirubinemia, and bacterial meningitis; neonatal intensive care unit (NICU) admission for > 5 days; exchange transfusion; and ototoxic drug use (aminoglycosides or loop diuretics), between the hearing disability and control groups. RESULTS: The total number of newborns came to 3,164,825. Risk factors were sought in a hearing disability group (n = 847) compared to a control group (n = 2508). A diagnosed disability other than a hearing disability, which was commonly a brain lesion, the use of ototoxic drugs, NICU admission for >5 days, and a maternal disability at delivery, which was commonly a hearing disability, were significant neonatal and maternal risk factors for HL in children. CONCLUSIONS: Accompanying brain lesions, maternal hearing disabilities at delivery, use of ototoxic drugs during the neonatal period, and hospitalization in NICU for >5 days were significant risk factors for HL in children, as revealed by analysis of population-based data.

Risk factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections: a nationwide population-based study.

BACKGROUND: The coronavirus disease 2019 (COVID-19) has rapidly turned into a public health emergency worldwide; however, the risk factors for infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have not been well-described. We aimed to identify the clinical risk factors for SARS-CoV-2 infections in Korea, where social distancing and face masks have been strongly recommended. METHODS: The data of individuals who underwent the reverse transcription polymerase chain reaction test for SARS-CoV-2 between January 3 and May 31, 2020 were retrieved from the Health Insurance Review and Assessment Service dataset. We used multivariable logistic regression models to identify the risk factors for SARS-CoV-2 infections in the population. RESULTS: We retrieved the results of 219,729 SARS-CoV-2 tests, of which 7,333 were positive results. In the multivariable analysis, female sex was associated with a higher risk of testing positive for SARS-CoV-2 [odds ratio (OR) =1.30, 95% confidence interval (CI): 1.24-1.37, P<0.0001]. Additionally, populations living in areas that had large outbreaks of COVID-19 were at an increased risk of testing positive for SARS-CoV-2 (OR =6.87, 95% CI: 6.55-7.21, P<0.0001). The odds of a positive test were greater for the Medical Aid beneficiaries (OR =1.99, 95% CI: 1.82-2.18, P<0.0001) than for the National Health Insurance beneficiaries. Individuals with diabetes mellitus (DM) were more likely to test positive (OR =1.15, 95% CI: 1.07-1.24, P=0.0002). CONCLUSIONS: Women, individuals living in areas with large outbreaks of COVID-19, Medical Aid beneficiaries, and individuals with DM might have greater risks of contracting SARS-CoV-2 infections despite practicing social distancing and using face masks.

Effects of BMI and LDL-cholesterol change pattern on cardiovascular disease in normal adults and diabetics.

INTRODUCTION: To examine how the risk of cardiovascular disease changes according to degree of change in body mass index (BMI) and low-density lipoprotein (LDL)-cholesterol in patients with diabetes using the health medical examination cohort database of the National Health Insurance Service in Korea. In comparison, the pattern in a non-diabetic control group was also examined. RESEARCH DESIGN AND METHODS: The study samples were 13 800 patients with type 2 diabetes and 185 898 non-diabetic controls, and their baseline characteristics and repeatedly measured BMI and LDL-cholesterol until occurrence of cardiovascular disease were collected in longitudinal data. We used the variability model that is joint of mixed effects and regression model, then estimated parameters about variability by Bayesian methods. RESULTS: The risk of cardiovascular disease was increased significantly with high average real variability (ARV) of BMI in the patients with diabetes, but the risk of cardiovascular disease was not increased according to degree of ARV in non-diabetic controls. The Bayesian variability model was used to analyze the effects of BMI and LDL-cholesterol change pattern on development of cardiovascular disease in diabetics, showing that variability did not have a statistically significant effect on cardiovascular disease. This shows the danger of the former simple method when interpreting only the mean of the absolute value of the variation. CONCLUSIONS: The approach of simple SD in previous studies for estimation of individual variability does not consider the order of observation. However, the Bayesian method used in this study allows for flexible modeling by superimposing volatility assessments on multistage models.

Panoramic radiography can be an effective diagnostic tool adjunctive to oral examinations in the national health checkup program.

PURPOSE: We investigated correlations between the findings of oral examinations and panoramic radiography in order to determine the efficacy of using panoramic radiographs in screening examinations. METHODS: This study included patients who visited dental clinics at National Health Insurance Service (NHIS) Ilsan Hospital for checkups during 2009-2015 and underwent panoramic radiographic examinations within 1 year prior to the oral examinations. Among the 48,006 patients who received checkups, 1,091 were included in this study. The data were evaluated using the Cohen kappa and interrater agreement coefficients. Accuracy, sensitivity, and specificity were calculated using data from the panoramic radiographs as true positive diagnoses. RESULTS: The interrater agreement coefficient for occlusal caries was 28.8%, and the Cohen kappa coefficient was 0.043 between the oral and panoramic radiographic examinations. Root caries and subgingival calculus were only found on the radiographs, while gingival inflammation was found only by the oral examinations. The oral examinations had a specificity for detecting occlusal dental caries of 100%, while their sensitivity for proximal dental caries and supragingival calculus was extremely low (14.0% and 18.3%, respectively) compared to the panoramic radiographic examinations. The oral examinations showed a relatively low sensitivity of 66.2% and a specificity of 43.7% in detecting tooth loss compared with panoramic radiography. CONCLUSIONS: Panoramic radiography can provide information that is difficult to obtain in oral examinations, such as root caries, furcation involvement, and subgingival calculus, which are factors that can directly affect the survival rate of teeth. It therefore seems reasonable and necessary to add panoramic radiography to large-scale health checkup programs such as that provided by the NHIS.

Association between periodontal disease and non-communicable diseases: A 12-year longitudinal health-examinee cohort study in South Korea.

The National Health Insurance Service-Health Examinee Cohort during 2002 to 2013 was used to investigate the associations between periodontal disease (PD) and the following non-communicable diseases (NCDs): hypertension, diabetes mellitus, osteoporosis, cerebral infarction, angina pectoris, myocardial infarction, and obesity.Univariate and multivariate logistic regression analyses adjusting for potential confounders during the follow-up period-including age, sex, household income, insurance status, residence area, health status, and comorbidities-were used to estimated odds ratios (ORs) with 95% confidence intervals (CIs) in order to assess the associations between PD and NCDs.We enrolled 200,026 patients with PD and 154,824 subjects with a healthy oral status. Statistically, significant associations were found between PD and the investigated NCDs except for cerebral and myocardial infarction after adjusting for sociodemographic and comorbidity factors (P < .05). In particular, obesity (OR = 1.30, 95% CI = 1.04-1.63, P = .022), osteoporosis (OR = 1.22, 95% CI = 1.18-1.27, P < .001), and angina pectoris (OR = 1.22, 95% CI = 1.17-1.27, P < .001) were significantly and positively associated with PD.This longitudinal cohort study has provided evidence that patients with PD are at increased risk of NCDs. Further studies are required to confirm the reliability of this association and elucidate the role of the inflammatory pathway in periodontitis pathogenesis as a triggering and mediating mechanism.

Development of methane and nitrous oxide emission factors for the biomass fired circulating fluidized bed combustion power plant.

This study makes use of this distinction to analyze the exhaust gas concentration and fuel of the circulating fluidized bed (CFB) boiler that mainly uses wood biomass, and to develop the emission factors of Methane (CH(4)), Nitrous oxide (N(2)O). The fuels used as energy sources in the subject working sites are Wood Chip Fuel (WCF), RDF and Refused Plastic Fuel (RPF) of which heating values are 11.9 TJ/Gg, 17.1 TJ/Gg, and 31.2 TJ/Gg, respectively. The average concentrations of CH(4) and N(2)O were measured to be 2.78 ppm and 7.68 ppm, respectively. The analyzed values and data collected from the field survey were used to calculate the emission factor of CH(4) and N(2)O exhausted from the CFB boiler. As a result, the emission factors of CH(4) and N(2)O are 1.4 kg/TJ (0.9-1.9 kg/TJ) and 4.0 kg/TJ (2.9-5.3 kg/TJ) within a 95% confidence interval. Biomass combined with the combustion technology for the CFB boiler proved to be more effective in reducing the N(2)O emission, compared to the emission factor of the CFB boiler using fossil fuel.