Korea National Health Insurance Research Articles

Epidemiology of Marfan syndrome: a retrospective cohort study based on the Korean population: A retrospective cohort study

Purpose: To determine the risk of incidence, prevalence, survival, and death risk for Marfan syndrome (MFS) in Korea.Methods: MFS (10th revision of the International Statistical Classification of Diseases [ICD-10] code: Q87.4) data were collected from the Korea National Health Insurance Service between 2006 and 2017. Simple and multiple Cox proportional hazards analyses were performed. The death data of Koreans from 2006 to 2018 were used.Results: The mean age of patients with MFS was 27.2± 16.8 years, 26.5± 15.9 years for males and 28.2± 18.1 years for females (P < 0.01), and the proportion of males was 59.5%. The age-standardized incidence and prevalence in 2017 were 0.51 and 5.70 per 100,000 persons, respectively. The 10-year survival rate was 92.7%. Adjusted hazard ratio increased significantly with age, male sex, heart failure, ischemic stroke, hemorrhagic stroke, chronic kidney disease, malignant neoplasm, aortic dissection, and abdominal aortic aneurysm.Conclusion: Although the overall 10-year survival rate of MFS was over 90%, the adjusted hazard ratio was significantly higher in the older age group, male sex, and individuals with heart failure, stroke, chronic kidney disease, malignant neoplasm, aortic dissection, and abdominal aortic aneurysm. These results suggest the need for meticulous surveillance of aortopathy in patients with MFS, as it may portend a worse prognosis in aortic dissection and aneurysm, and in older age groups with MFS.

Risk of Nephrolithiasis Associated With SGLT2 Inhibitors Versus DPP4 Inhibitors Among Patients With Type 2 Diabetes: A Target Trial Emulation Study.

We aim to compare the risk of nephrolithiasis among type 2 diabetes patients who initiated sodium-glucose cotransporter-2 inhibitors (SGLT2is) versus dipeptidyl-peptidase-4 inhibitors (DPP4is), individually within stone never- and ever-formers. Using the 2010-2021 Korea National Health Insurance Service database, we conducted a population-based cohort study, comparing initiators of SGLT2is versus DPP4is. The primary outcome was incident nephrolithiasis. Osteoarthritis encounters served as a negative control outcome. After 1:1 propensity score (PS) matching in stone never- and ever-formers, pooled and individual hazard ratios (HRs), incidence rate difference (IRD), and 95% CIs were reported. Subgroup analyses by sex, age, thiazide co-use, and baseline cardiovascular risk were done. The 17,006 PS-matched pairs of SGLT2i and DPP4i initiators were pooled from stone never- (105,378 pairs) and ever-formers (11,628 pairs). Over a mean of 654 days, the risk of nephrolithiasis was lower in SGLT2i initiators than in DPP4i: 0.65 vs. 1.12 events per 100 person-years, HR 0.54 (95% CI, 0.50-0.57), IRD -0.46 (95% CI,-0.21 to -0.52). Among never-formers, the HR was 0.43 (95% CI, 0.39-0.48) and IRD was -0.32 (95% CI,-0.27 to -0.36). Among ever-formers, the HR was 0.64 (95% CI, 0.59-0.69) and IRD was -2.26 (95% CI,-1.77 to -2.76). Near-null associations were found for osteoarthritis encounters. Results were consistent across subgroups. We found a lower risk of nephrolithiasis associated with SGLT2is versus DPP4is in stone never- and ever-formers. Despite a greater relative risk reduction in the former, the absolute risk reduction was greater in the latter.

Resolution of hypertension after kidney transplantation is associated with improved kidney transplant outcomes: a nationwide cohort study.

Patients with advanced chronic kidney disease suffer from hypertension, and kidney transplantation (KT) has potential to induce hypertension resolution. We hypothesized that hypertension resolution after KT is associated with better KT outcomes. We identified KT recipients (2006-2015) who had pretransplant hypertension. They were categorized into two groups based on their hypertension status after KT: persistent vs. resolved hypertension, using data from the Korea National Health Insurance System. Cox proportional hazard analyses were performed to assess the risk of graft failure and mortality, adjusting for various clinical factors. Among 11 317 KT recipients with pretransplant hypertension, 7269 (64%) remained hypertensive, while 4048 (36%) experienced hypertension resolution. Recipients with resolved hypertension exhibited a lower prevalence of delayed graft function and major comorbidities, including diabetes, ischemic heart disease, and stroke. Graft failure and mortality rates were significantly lower in resolved hypertension group. After adjusting for multiple covariates, hazard ratios of resolved hypertension were 0.61 (95% confidence interval 0.52-0.72) for graft failure and 0.68 (0.56-0.81) for all-cause mortality. A significant proportion of patients experienced hypertension resolution after KT, which is associated with improved graft and overall survival. The post-KT hypertension resolution can be used as a prognostic indicator for predicting better KT outcomes.

Factors Associated With Medical Expenses Among Long-Term Care Insurance Recipients Aged 65 Years or Older in Korea.

This study examined the factors associated with medical expenses among LTCI (long-term care insurance) recipients in Korea. Secondary data analysis was performed using the 2019 Korea National Health Insurance (KNHI) reimbursement data of I metropolitan city. Data from 52 434 older adults who were LTCI recipients and living in I metropolitan city areas were included. Based on the Andersen healthcare utilization model, the variables included the predisposing (age, sex, and living alone), enabling (health insurance and place of residence), and need factors (disability, LTC grade, use of LTCI services, and participation in health screening). All the predisposing, enabling, and need factors were significant. Older age, higher LTC grade, use of visiting nursing service, admission to an aged care facility, and participation in health screenings were negatively associated with medical expenses. Females, those living alone, non-disabled individuals, medical aid beneficiaries, and rural residents were less likely to incur medical expenses. Appropriate use of LTCI services (e.g., visiting nursing) will help reduce unnecessary medical expenses. Nevertheless, access to health care services for older adults living alone in rural areas must be improved.

Combined Effects of Air Pollution and Changes in Physical Activity With Cardiovascular Disease in Patients WithDyslipidemia.

Sedentary behavior elevates cardiovascular disease (CVD) risk in patients with dyslipidemia. Increasing physical activity (PA) is recommended alongside pharmacological therapy to prevent CVD, though benefits across environmental conditions are unclear. We analyzed data from 113 918 newly diagnosed patients with dyslipidemia (2009-2012) without prior CVD, sourced from the Korea National Health Insurance Service. Ambient particulate matter (PM) 2.5 and PM10 levels were collected from the National Ambient Air Monitoring System in South Korea. Changes in PA, measured in metabolic equivalents of task-min/wk before and after dyslipidemia diagnosis, were evaluated for associations with air pollution levels and CVD risk using Cox proportional hazards regression. Patients were followed from January 1, 2013, until CVD onset, death, or December 31, 2021. Among patients exposed to low to moderate PM2.5 levels (≤25 μg/m3), increasing PA from inactive to ≥1000 metabolic equivalents of tasks-min/wk was associated with a lower risk of CVD (adjusted hazard ratio, 0.82 [95% CI, 0.70-0.97]; P for trend=0.022). In high PM2.5 (>25 μg/m3) conditions, increasing PA from inactive and decreasing PA from ≥1000 metabolic equivalents of task-min/wk was associated with reduced (P for trend=0.010) and elevated (P for trend=0.028) CVD risks, respectively. For PM10, increased PA was linked to reduced CVD risk (P for trend=0.002) and decreased PA to elevated risk (P for trend=0.042) in low to moderate PM10 (≤50 μg/m3) conditions, though benefits diminished at high PM10 (>50 μg/m3) exposures. Promoting PA, while considering the high potential cardiovascular risk associated with air pollution, may be an effective intervention against CVD in patients with dyslipidemia.

Abstract 4113188: Increased Physical Activity Intensity Associated with Reduced Risk of Atrial Fibrillation among Older Adults in South Korea: A Retrospective Cohort Study

Introduction: Physical activity (PA) may be associated with a lower risk of atrial fibrillation (AF), but this relationship remains controversial. In particular, further research is needed on the association between changes in PA intensity and AF risk among older adults. Hypothesis: We hypothesized that an increase in PA intensity would be associated with a reduced risk of AF among older adults aged 65 years and older in South Korea. Aim: This cohort study aimed to evaluate the association between changes in metabolic equivalent tasks (METs)-min/week and the risk of AF in the elderly using a nationally representative database. Methods: We conducted a retrospective cohort study using the Korea National Health Insurance Service (KNHIS) database. This cohort included 1,726,697 individuals aged 65 years and older without a history of cardiovascular disease diagnosis who underwent two consecutive health screening examinations from 2009 to 2012. PA was defined as MET-min/week derived from two consecutive health examinations during 2009-2010 (1st period) and 2011-2012 (2nd period), respectively. The primary outcome was an AF diagnosis during the follow-up period from 2013 to 2021. We estimated the sub-distribution hazard ratio (sHR) and 95% confidence interval (CI) for the association of changes in PA intensity with AF using Fine-Gray sub-distribution hazard models after adjustment for covariates. Results: This study included 1,726,697 participants (mean age 71.08; 46.78% male). An increase in PA intensity was associated with a reduced risk of AF (P for trend<0.001). Compared to persisting in physical inactivity, a change in PA intensity from physically inactive to ≥1000 MET–min/week was associated with a lower risk of AF (sHR, 0.83, 95% CI, 0.81-0.85). In contrast, a change in PA intensity from ≥1000 MET–min/week to being physically inactive was associated with a higher risk of AF (sHR, 1.30, 95% CI, 1.27-1.33) as compared to persistence in ≥1000 MET–min/week of PA intensity. Conclusions: An increase in MET-min/week may be associated with a reduced risk of AF among adults aged 65 years and older. Therefore, interventions encouraging PA should be recommended to maximize the health benefits of AF prevention in the elderly.

Cholecystectomy Increases the Risk of Chronic Kidney Disease: A Nationwide Longitudinal Cohort Study.

Background/Objectives: Growing evidence suggests that cholecystectomy is associated with adverse health outcomes, including the development of metabolic diseases. However, data on the association between cholecystectomy and kidney disease are limited. The present study aimed to investigate the association between cholecystectomy and chronic kidney disease (CKD) using a nationwide longitudinal cohort. Methods: Participants aged ≥20 years with cholecystectomy between 2010 and 2014 (n = 116,748) and age- and sex-matched control participants without cholecystectomy (n = 116,748) were analyzed using the Korea National Health Insurance Service data. The adjusted hazard ratios (aHRs) were calculated for incident CKD in the cholecystectomy group compared with the nonoperative controls. Results: A total of 233,496 participants were included (mean age, 54.7 ± 12.7 years; 52.6% men). During the mean follow-up period of 4.8 ± 1.7 years, 6450 patients (5.5%) were newly diagnosed with CKD in the cholecystectomy group. Cholecystectomy was an independent risk factor for the development of CKD after adjustment for confounders, including age, sex, income, health behaviors, and comorbidities. The risk of CKD was 21% higher in the cholecystectomy group compared to the non-cholecystectomy group (aHR, 1.21; 95% CI, 1.17-1.26). The increased risk of CKD in the cholecystectomy group was consistently significant when a stratified analysis by age, sex, and presence or absence of comorbidities was conducted. Conclusions: Cholecystectomy was independently associated with an increased risk of developing CKD in a nationwide population-based study. Therefore, careful and long-term monitoring of the risk of CKD after cholecystectomy is necessary.

Healthcare utilization among foreign beneficiaries of the National Health Insurance program in Korea.

To explore the factors related to healthcare utilization (both inpatient and outpatient services) among foreign beneficiaries of the National Health Insurance (NHI) in Korea. The total foreign beneficiaries of the NHI in Korea 2022 were included (n = 1,386,329). For the dependent variables, utilization and either hospital stays or count of visits were used. And the independent variables were selected guided by Andersen's behavioral framework: predisposing characteristics (e.g., sex, age, nationality), enabling characteristics (e.g., insurance premium ranking, residency status, residency period, place of residency, beneficiary type), and need characteristics (e.g., disability, CCI, chronic diseases). We conducted a two-part model analysis employing Andersen's behavioral framework, using health insurance claims data from 2022. The results indicated that individual need characteristics, such as disability, CCI, and chronic diseases, had the most significant impact on total healthcare utilization and its associated costs. The next significant characteristic was the residence period; the longer the period, the higher the likelihood of healthcare utilization, but the lower the associated costs. Among the predisposing characteristics, individuals aged 65 years and older had the most significant impact on healthcare costs. Additionally, among the enabling characteristics, residency period, residency status, and beneficiary type were most significant. Foreigners residing in Korea are eligible to use the Korean healthcare system by enrolling in NHI. As the foreign population is projected to grow even faster due to Korea's aging society and low birth rate, this study can assist public health administrators in formulating evidence-based policies.

Ocular Adverse Events Following Coronavirus Disease 2019 Infection: A Self-controlled Case Series Study from the Entire Korean Population

This study aimed to assess the risk of ocular adverse events, including retinal artery occlusion (RAO), retinal vein occlusion (RVO), noninfectious uveitis (NIU), noninfectious scleritis (NIS), optic neuritis (ON), ischemic optic neuropathy (ION), and ocular motor cranial nerve palsy (OMCNP), after coronavirus disease 2019 (COVID-19) infection. Population-based self-controlled case series (SCCS). The study included patients from the entire Korean population of 52 million who experienced incident RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, or OMCNP between January 1, 2021, and October 29,2022. This nationwide SCCS utilized data from the Korea National Health Insurance Service and the Korea Disease Control and Prevention Agency. The risk period after infection was defined as up to 24 weeks after COVID-19 infection. Conditional Poisson regression was used to calculate the relative incidence rate ratios (IRRs) for RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, and OMCNP during the designated risk periods. The IRRs for RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, and OMCNP during the risk periods. The study included 9336, 103362, 201010, 25428, 23744, 3026, 69933, and 16335 cases of incident RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, and OMCNP, respectively. The IRRs (95% confidence interval) during the early risk period (1-8 weeks) were 0.94 (0.83-1.07), 1.01 (0.97-1.04), 1.00 (0.98-1.03), 0.96 (0.90-1.03), 1.00 (0.94-1.07), 0.97 (0.81-1.17), 0.97 (0.93-1.01), and 1.02 (0.94-1.11), respectively. In the late risk period (9-24 weeks), the IRRs were 1.02 (0.92-1.12), 1.01 (0.98-1.04), 1.01 (0.99-1.03), 1.02 (0.97-1.08), 1.02 (0.97-1.08), 0.99 (0.85-1.15), 1.02 (0.99-1.06), and 0.97 (0.90-1.03), respectively. Stratified analyses showed that in patients with a history of cerebro-cardiovascular disease, the risk of RAO increased during the late risk period, with an IRR (95% confidence interval) of 1.19 (1.02-1.40). The risk of incident RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, or OMCNP did not increase after COVID-19 infection. The risk of incident RAO increased only in individuals with preexisting cardio-cerebrovascular disease. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Fatty liver index and development of lung cancer: a nationwide cohort study.

This study aimed to evaluate the impact of steatotic liver disease severity on the cumulative incidence of lung cancer utilizing data from the Korea National Health Insurance Service (NHIS). This study examined the risk of lung cancer in the general population in conjunction with the incidence of steatotic liver disease. The study population consisted of 3,261,438 individuals aged 20 years or older who underwent a general health examination in 2009. Individuals with fatty liver index (FLI) of 30-59 exhibited a 1.08-fold increased risk of lung cancer (95% CI: 1.04-1.11), while FLI ≥ 60 was associated with a 1.22-fold elevated risk of lung cancer (95% CI: 1.17-1.28) compared to those with FLI < 30. The risk varied with smoking status; in current smokers, the adjusted HR for the FLI 30-59 group was 1.05 (95% CI: 1.00-1.10), while that in the FLI ≥ 60 group was 1.11 (95% CI: 1.04-1.18). In never- or past-smokers, the adjusted HR for the FLI 30-59 group was 1.10, and that for the FLI ≥ 60 group was 1.31. Subgroup analysis revealed an incidence rate of 1.06 per 1,000 person-years in the consistently high FLI group compared to 1.15 in those with improved FLI. Improving FLI over time was associated with a 0.93-fold decrease in lung cancer risk. Our study demonstrated a correlational relationship between lung cancer incidence and the severity of steatotic liver disease as measured by FLI.

Trajectories of triglyceride-glucose index changes and their association with all-cause and cardiovascular mortality: a competing risk analysis

BackgroundThe association between changes in insulin resistance, reflected by the triglyceride-glucose (TyG) index, and mortality remains unclear. This study investigated whether longitudinal trajectories of TyG index changes are associated with all-cause and cardiovascular disease (CVD) mortality.MethodsThis retrospective cohort study analyzed data from 233,546 adults aged ≥ 19 years from the Korea National Health Insurance Service-National Sample Cohort. Participants were categorized as having increasing, stable, or decreasing TyG index changes during a 4-year exposure period (2009–2014). Mortality outcomes were assessed during an 8.13-year follow-up period (2015–2021). Cox proportional hazards regression and competing risk analysis were used to evaluate all-cause and CVD mortality.ResultsA total of 7918 mortality events, including 651 CVD deaths, were recorded. Compared with the stable group, adjusted hazard ratios for all-cause mortality were 1.09 (95% CI 1.03–1.15) in the increasing group and 1.23 (95% CI 1.01–1.50) for CVD mortality. An increased TyG index was significantly associated with all-cause mortality in individuals aged < 50 years; men; and individuals with obesity, hypertension, diabetes, and/or dyslipidemia. For CVD mortality, significant associations were found in individuals aged 50–69 years, with obesity, with diabetes, or without dyslipidemia.ConclusionAn increasing TyG index from baseline during follow-up was independently associated with higher risks of all-cause and CVD mortality. Serial monitoring of TyG index changes could enhance risk stratification and inform targeted interventions to reduce insulin resistance, and ultimately lower mortality risk.

7115 Long-Term Exposure To Air Pollution And Precocious Puberty In Korea

Abstract Disclosure: J. Choi: None. J. Oh: None. R. Lee: None. E. Mun: None. K. Kim: None. E. Ha: None. H. Kim: None. Backgrounds and Aims The increasing prevalence of precocious puberty is emerging as a significant medical and social problem worldwide. However, limited research has investigated the relationship between long-term air pollution exposure and precocious puberty. We aimed to investigate the association between long-term air pollution exposure and first onset of precocious puberty in South Korea, nationwide. Methods: We investiagted a retrospective cohort using Korea National Health Insurance Database. Children born from 2007 to 2009 were followed-up from the age of six (2013 to 2015). We included boys aged ≤10 years and girls aged ≤ 9 years who visited hospitals for early pubertal development and were diagnosed with precocious puberty according to the ICD-10 (E228, E301,and E309) and gonadotropin-releasing hormone agonist (GnRHa) treatment. We conducted the association between long-term air pollution exposure and first onset of precocious puberty using a Cox proportional hazard model. We estimated the hazard ratios (HR) and 95% confidence intervals (CI) per 1 μg/m3 increase for fine particulate matter (PM2.5) and particulate matter (PM10) and per 1 ppb increase for sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3). Results: A total of 1,205,784 childrens aged six years old were included during 2013­-2015. A positive association was found that the association between 48-month moving average PM2.5 (HR: 1.019, 95% CI: 1.012, 1.027), PM10 (HR: 1.009, 95% CI: 1.006, 1.013), SO2 (HR: 1.037, 95% CI: 1.018, 1.055), O3 (HR: 1.006, 95% CI: 1.001, 1.010) exposure and precocious puberty in girls. In contrast, no association was found in boys. Conclusions Our findings supported that long-term exposure to air pollution is associated with an increased risk of precocious puberty. The study provides valuable insights into the harmful effects of air pollution during childhood and adolescence, emphasizing that air pollution is a modifiable risk factor that can be managed and improved. Presentation: 6/1/2024

Analyzing the dynamics of complicated and uncomplicated appendicitis during the COVID-19 pandemic in Seoul, Korea: a multifaceted time series approach.

This study investigated the impact of the coronavirus disease 2019 (COVID-19) pandemic and associated control strategies on the incidence of appendicitis in Seoul, using data from 2018 to 2020 from Korea's National Health Insurance. We analyzed records of total, complicated, and uncomplicated appendicitis cases, as well as the ratio of complicated to uncomplicated appendicitis, using natural spline and piecewise regression models to identify trends and breakpoints. Bayesian structural time-series (BSTS) models were used to evaluate the causal impact of social distancing on appendicitis incidences. The spline regression analysis indicated decreasing trends in both total and uncomplicated appendicitis cases. Conversely, the incidence of complicated appendicitis and the ratio of complicated to uncomplicated cases increased. Breakpoints for a decline in uncomplicated appendicitis and a rise in the ratio occurred at 31 weeks in 2020 (95% confidence interval [CI], 23.2 to 38.8) and at 33.9 weeks (95% CI, 28.3 to 39.6), respectively. The BSTS model demonstrated a 7.8% reduction in total appendicitis cases (95% credible interval [CrI], -12.1 to -3.3). It also showed a 17.4% decrease in uncomplicated cases (95% CrI, -22.2 to -12.3) and increases of 12.8% (95% CrI, 4.9 to 22.0) in complicated cases and 39.0% (95% CrI, 27.0 to 53.3) in the ratio of complicated to uncomplicated appendicitis. The COVID-19 pandemic resulted in a decrease in both total and uncomplicated appendicitis cases, while the number of complicated cases increased. Reduced medical visits likely accounted for these changes. Strategies are needed to manage changes in disease pathophysiology resulting from altered healthcare utilization during health crises.

Incidence of metabolic dysfunction-associated steatotic liver disease and advanced fibrosis and impact of overweight/obesity in elderly population: a nationwide cohort study.

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing worldwide, coinciding with aging population. However, limited studies have evaluated its incidence and progression to advanced fibrosis in the elderly population. Therefore, our study aimed to investigate the incidence of MASLD and advanced fibrosis in this age group. We included 878 686 individuals aged ≥60years from the Korea National Health Insurance Service-Senior cohort. After excluding participants with preexisting MASLD, 329 388 individuals were finally analyzed. Participants were categorized into four groups based on the presence of overweight/obesity and additional risk factors (aRF) included in the cardiometabolic diagnostic criteria of MASLD. The overall incidence of MASLD was 1.94 per 100 person-years, and the incidence of advanced fibrosis in MASLD patients was 1.78 per 100 person-years. MASLD development was significantly higher in overweight/obese patients (2.65 per 100 person-years) compared to lean patients (1.09 per 100 person-years), and this trend persisted after stratification by the presence of aRF. Similarly, the incidence of advanced fibrosis among MASLD patients was higher in overweight/obese individuals (2.06 per 100 person-years) compared to lean counterparts (0.87 per 100 person-years), irrespective of aRF. The lower incidence of MASLD in the elderly population compared to the general population underscores the importance of identifying age-specific risk factors. Overweight/obesity emerged as a robust predictor of MASLD development and advanced fibrosis. Additionally, the presence of additional cardiometabolic risk factors further increased the risk of incident MASLD and advanced fibrosis among the elderly.

Common Cancer-Related Factors and the Risk of Developing Kaposi Sarcoma in Individuals without AIDS: Korea National Health Insurance Services Claims Database.

Backgrounds: Kaposi sarcoma (KS) is a unique form of cancer with epidemiological characteristics distinct from those of other solid cancers. While common risk factors including alcohol consumption, smoking, and metabolic disorders have been well studied in various cancers, their relationship with KS remains unclear. Methods: This study used a cohort approach with adults without AIDS, utilizing data from the National Health Insurance Service in South Korea. This study examined various conventional cancer-related risk factors related to the incidence of KS, including psoriasis. Results: Alcohol consumption, smoking, body mass index, diabetes mellitus, hypertension, hypercholesterolemia, and regular exercise were not significantly associated with the incidence of KS. Additionally, older age and male sex were associated with a higher incidence of KS. KS risk was increased in pathological conditions such as psoriasis and proteinuria, which require immunosuppressive medication. Conclusions: Our study suggests that traditional cancer-related risk factors may not play a significant role in the pathogenesis of KS, unlike other cancers. This, in turn, emphasizes the importance of immunosuppression and HHV-8 infection in the development of KS.

Cancer risk among air transportation industry workers in Korea: a national health registry-based study

BackgroundFlight attendants face various risk factors in their working environments, particularly occupational exposure to cosmic radiation. This study aimed to assess cancer risk among air transportation industry workers, including flight attendants, in Korea by constructing a cohort using national health registry-based data and analyzing cancer incidence risk.MethodsWe used the Korea National Health Insurance Service database from 2002 to 2021 to construct a cohort of 37,011 workers in the air transportation industry. Cancer incidence was defined using the tenth version of the International Classification of Diseases. We calculated the age- and sex-specific standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) by applying the cancer incidence rate of the general population between 2002 and 2019.ResultsApproximately 5% of the cohort developed cancer. Overall, the cancer incidence in the cohort was similar to or lower than that of the general population, with the SIRs for all cancers being lower. However, significantly higher SIRs were observed for nasopharyngeal cancer (SIR, 3.21; 95% CI, 1.71–5.48) and non-Hodgkin lymphoma (SIR, 1.57; 95% CI, 1.02–2.32) in male workers and breast and genital cancer (SIR, 1.51; 95% CI, 1.34–1.70) and thyroid cancer (SIR, 1.25; 95% CI, 1.05–1.47) in female workers.ConclusionsThe lower overall cancer incidence among air transportation industry workers observed in this study could indicate the “healthy worker effect”; however, the incidences of certain cancers were higher than those in the general population. Given that these workers are exposed to multiple occupational and lifestyle-related risk factors, including cosmic radiation, further studies are necessary to determine radiation-induced cancer risk while considering potential confounding factors.

COVID-19 Vaccination and Ocular Adverse Events: A Self-Controlled Case Series Study From the Entire South Korean Population

This study aimed to assess the risk of ocular adverse events, including retinal artery occlusion (RAO), retinal vein occlusion (RVO), noninfectious uveitis (NIU), noninfectious scleritis (NIS), optic neuritis (ON), ischemic optic neuropathy (ION), and ocular motor cranial nerve palsy (OMCNP), following Coronavirus Disease 2019 (COVID-19) vaccination. Population-based self-controlled case series METHODS: This study utilized nationwide claims and vaccination data provided by the Korea National Health Insurance Service and Korea Disease Control and Prevention Agency. From the entire South Korean population of 52 million individuals, patients with incident RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, or OMCNP between January 2021 and March 2022 were included. The postvaccination risk period was defined as up to 56 days after COVID-19 vaccination. The relative incidence rate ratios (IRRs) for RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, and OMCNP during the risk periods were measured using conditional Poisson regression. The study included 6,590, 70,120, 137,958, 17,921, 15,492, 2,039, 49,089, and 11,312 cases of incident RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, and OMCNP, respectively. The IRRs (95% confidence interval) during the early risk period (0-28 days) were 0.95 (0.88-1.01), 0.96 (0.94-0.98), 0.93 (0.91-0.94), 0.93 (0.89-0.96), 0.96 (0.92-1.01), 1.04 (0.92-1.18), 0.98 (0.95-1.00), and 0.91 (0.86-0.96), respectively. In the late risk period (29-56 days), the IRRs were 0.96 (0.89-1.03), 0.93 (0.91-0.96), 0.96 (0.95-0.98), 1.00 (0.95-1.04), 0.96 (0.91-1.01), 1.00 (0.87-1.15), 1.01 (0.98-1.04), and 0.95 (0.90-1.01), respectively. COVID-19 vaccination did not increase the risk of incident RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, or OMCNP during the postvaccination period.

Impact of early economic activity loss on all-cause mortality in gastric cancer survivors following curative treatment: a nationwide study in Korea.

The impact of economic engagement on the health of cancer survivors is notable. Our study aims to explore the association between early loss of economic activity (EA) and the risk of all-cause mortality among gastric cancer survivors. This retrospective cohort study utilized data from Korea's National Health Insurance Service, focusing on 30-59-year-old gastric cancer patients who received either surgery or endoscopic procedures from January 2009 to December 2013. The primary outcome measure was all-cause mortality. Early loss of EA was identified when a patient's insurance status shifted to dependent within one year following treatment. Adjusted hazard ratios (HRs) and 95% confidence intervals (CI) for all-cause mortality were estimated using multivariable Cox proportional hazards models, conducting separate analyses for surgical and endoscopic groups. Among 24,159 patients (median follow-up, 9.9years), 2976 (12.3%) experienced all-cause mortality. Specifically, 2835 of these deaths occurred in patients who underwent surgery, while 141 were in the endoscopic procedure group. Early loss of EA was recorded in 14.4% of the surgery group and 7.7% of the endoscopic procedure group. Adjusted HRs (95% CI) for all-cause mortality associated with early loss of EA were 1.39 (1.27-1.54) for the surgery group and 2.27 (1.46-3.52) for the endoscopic procedure group. This study highlights a significant association between the early loss of EA and an increased risk of all-cause mortality in those who have undergone curative treatments for gastric cancer. It underscores the crucial role of sustaining EA in enhancing the health outcomes of these survivors.

Dementia Incidence in Survivors of Multiple Myeloma: A National Case-Control Study Conducted in Korea (The CAREMM-2106 Study)

BackgroundDementia, a growing global health issue, affects older adults and specific groups like long-term cancer survivors. The link between cancer survival and dementia is debated. Multiple myeloma (MM), a common blood cancer in older adults, is often linked with cognitive issues. This study investigated dementia incidence in long-term MM survivors using Korean national data. MethodsA retrospective case-control study used data from the Korea National Health Insurance Service (KNHIS), covering about 50 million Koreans. Patients diagnosed with MM between 2009 and 2020 formed the case cohort, while the control cohort included matched individuals without MM using propensity-score matching. Analyzing baseline characteristics, comorbidities, and socioeconomic status, the primary outcome was dementia incidence identified via ICD-10 codes. Statistical methods included Kaplan-Meier plots, cause-specific and Fine–Gray subdistribution hazard models, and a 3-year landmark analysis for immortal time bias. ResultsThe study included 33,864 patients, with 16,932 in each cohort. The overall cumulative dementia incidence was lower in the MM cohort compared to controls. However, in the first 3 years, MM patients had a higher dementia risk (HR: 1.711, 95% CI, 1.562-1.874) than controls. After 3 years, the risk significantly decreased (HR: 0.625, 95% CI, 0.560-0.696). Age-specific analysis showed a consistent pattern, particularly among MM patients aged 70-79, where dementia risk increased post-3 years. ConclusionThis study reveals a lower long-term dementia risk in MM survivors compared to non-MM individuals. Further prospective studies are needed to confirm these findings and explore the underlying mechanisms.

The Impact of Transcatheter Aortic Valve Implantation on Health Care Costs and Clinical Outcomes Based on Frailty Risk: A Nationwide Cohort Analysis

BackgroundTranscatheter aortic valve implantation (TAVI) is preferred for treating severe aortic stenosis in older, frail populations, yet the impact of frailty on economic and clinical outcomes of TAVI is not well studied. MethodsThis retrospective cohort study included 2175 TAVI patients from 2015 to 2019, using Korea's National Health Insurance Service database, stratifying patients into low, intermediate, and high-frailty groups, using the Hospital Frailty Risk Score (HFRS). Health care costs, admissions, and total length of hospitalization were analyzed using Wilcoxon-rank test 12 months pre- and post-TAVI. Composite endpoint of death, stroke, and major bleeding, with individual outcomes, were compared using χ2 tests and Kaplan-Meier analysis. ResultsMean age was 80.2 years, and 47.3% were male; 747 (34.3%) were low frailty, 1159 (53.3%) were moderate frailty, and 269 (12.4%) were high frailty. After TAVI, medical costs decreased in the intermediate- (pre-TAVI: 2,269,000 KRW [$1668 USD], post-TAVI: 1,607,000 KRW [$1181 USD]; P < 0.001) and high-frailty groups (pre-TAVI: 3,949,000 KRW [$2904 USD], post-TAVI: 2,188,000 KRW [$1609 USD]; P < 0.001). All frailty groups had shorter length of hospital stay post-TAVI (26 to 21 days in the low-frailty, 44 to 31 days in the intermediate-frailty, and 65 to 41 days in the high-frailty group; all P <0.001). The composite outcome was higher in the frailer groups (27.8% in the low-frailty vs 31.5% in the intermediate-frailty vs 37.9% in the high-frailty group; P = 0.008). All groups showed comparable rates of cardiovascular death, stroke, or bleeding. ConclusionsTAVI is clinically viable and cost-saving treatment option for frail patients with severe aortic stenosis.