Data Resource Profile: The Cancer Public Library Database in South Korea.

This paper provides a comprehensive overview of the Cancer Public Library Database (CPLD), established under the Korean Clinical Data Utilization for Research Excellence project (K-CURE). The CPLD links data from four major population-based public sources: the Korea National Cancer Incidence Database in the Korea Central Cancer Registry, cause-of-death data in Statistics Korea, the National Health Information Database in the National Health Insurance Service, and the National Health Insurance Research Database in the Health Insurance Review & Assessment Service. These databases are linked using an encrypted resident registration number. The CPLD, established in 2022 and updated annually, comprises 1,983,499 men and women newly diagnosed with cancer between 2012 and 2019. It contains data on cancer registration and death, demographics, medical claims, general health checkups, and national cancer screening. The most common cancers among men in the CPLD were stomach (16.1%), lung (14.0%), colorectal (13.3%), prostate (9.6%), and liver (9.3%) cancers. The most common cancers among women were thyroid (20.4%), breast (16.6%), colorectal (9.0%), stomach (7.8%), and lung (6.2%) cancers. Among them, 571,285 died between 2012 and 2020 owing to cancer (89.2%) or other causes (10.8%). Upon approval, the CPLD is accessible to researchers through the K-CURE portal. The CPLD is a unique resource for diverse cancer research to investigate medical use before a cancer diagnosis, during initial diagnosis and treatment, and long-term follow-up. This offers expanded insight into healthcare delivery across the cancer continuum, from screening to end-of-life care.

What is the relationship between the local population change and cancer incidence in patients with dyslipidemia: Evidence of the impact of local extinction in Korea.

BACKGROUND: Changes in the local population are intricately linked to healthcare infrastructure, which subsequently impacts the healthcare sector. A decreasing local population can result in lagging health infrastructure, potentially leading to adverse health outcomes as patients may be at risk of not receiving optimal care and treatment. While some studies have explored the relationship between chronic diseases and local population decline, evidence regarding cancer is insufficient. In this study, we focused on how deteriorating management of chronic diseases such as dyslipidemia could influence the risk of cancer. We investigated the relationship between changes in the local population and cancer incidence among patients with dyslipidemia. METHODS: This cohort study was conducted using claims data. Data from adult patients with dyslipidemia from the National Health Insurance Service-National Sample Cohort conducted between 2002 and 2015 were included. Population changes in each region were obtained from the Korean Statistical Information Service and were used to link each individual's regional code. Cancer risk was the dependent variable, and Cox proportional hazards regression was used to estimate the target associations. RESULTS: Data from 336,883 patients with dyslipidemia were analyzed. Individuals who resided in areas with a decreasing population had a higher risk of cancer than those living in areas with an increasing population (decrease: hazard ratio (HR) = 1.06, 95% CI = 1.03-1.10; normal: HR = 1.05, 95% CI = 1.02-1.09). Participants living in regions with a low number of hospitals had a higher risk of cancer than those in regions with a higher number of hospitals (HR = 1.20, 95% CI = 1.12-1.29). CONCLUSION: Patients in regions where the population has declined are at a higher risk of cancer, highlighting the importance of managing medical problems caused by regional extinction. This could provide evidence for and useful insights into official policies on population decline and cancer risk.

Relationship between patient outcomes and patterns of fragmented cancer care in older adults with gastric cancer: A nationwide cohort study in South Korea.

INTRODUCTION: Fragmented cancer care, defined as receipt of care from multiple hospitals, has been shown to be associated with poor patient outcomes and high expense. However, evidence regarding the effects of hospital choice by patients with cancer on overall survival are lacking. Thus, we investigated the relationship between patterns of fragmented care and five-year mortality in patients with gastric cancer. MATERIALS AND METHODS: Using the Korean National Health Insurance senior cohort of adults aged ≥60 years, we identified patients with gastric cancer who underwent gastrectomy during 2007-2014. We examined the distribution of the study population by five-year mortality, and used Kaplan-Meier survival curves/log-rank test and Cox proportional hazard model to compare five-year mortality with fragmented cancer care. RESULTS: Among the participants, 19.5% died within five years. There were more deaths among patients who received fragmented care, especially those who transferred to smaller hospitals (46.6%) than to larger ones (40.0%). The likelihood of five-year mortality was higher in patients who received fragmented cancer care upon moving from large to small hospitals than those who did not transfer hospitals (hazard ratio, 1.28; 95% confidence interval, 1.10-1.48, P = .001). Moreover, mortality was higher among patients treated in large hospitals or in the capital area for initial treatment, and this association was greater for patients from rural areas. DISCUSSION: Fragmentation of cancer care was associated with reduced survival, and the risk of mortality was higher among patients who moved from large to small hospitals.

Synthetic Tabular Data Based on Generative Adversarial Networks in Health Care: Generation and Validation Using the Divide-and-Conquer Strategy.

BACKGROUND: Synthetic data generation (SDG) based on generative adversarial networks (GANs) is used in health care, but research on preserving data with logical relationships with synthetic tabular data (STD) remains challenging. Filtering methods for SDG can lead to the loss of important information. OBJECTIVE: This study proposed a divide-and-conquer (DC) method to generate STD based on the GAN algorithm, while preserving data with logical relationships. METHODS: The proposed method was evaluated on data from the Korea Association for Lung Cancer Registry (KALC-R) and 2 benchmark data sets (breast cancer and diabetes). The DC-based SDG strategy comprises 3 steps: (1) We used 2 different partitioning methods (the class-specific criterion distinguished between survival and death groups, while the Cramer V criterion identified the highest correlation between columns in the original data); (2) the entire data set was divided into a number of subsets, which were then used as input for the conditional tabular generative adversarial network and the copula generative adversarial network to generate synthetic data; and (3) the generated synthetic data were consolidated into a single entity. For validation, we compared DC-based SDG and conditional sampling (CS)-based SDG through the performances of machine learning models. In addition, we generated imbalanced and balanced synthetic data for each of the 3 data sets and compared their performance using 4 classifiers: decision tree (DT), random forest (RF), Extreme Gradient Boosting (XGBoost), and light gradient-boosting machine (LGBM) models. RESULTS: The synthetic data of the 3 diseases (non-small cell lung cancer [NSCLC], breast cancer, and diabetes) generated by our proposed model outperformed the 4 classifiers (DT, RF, XGBoost, and LGBM). The CS- versus DC-based model performances were compared using the mean area under the curve (SD) values: 74.87 (SD 0.77) versus 63.87 (SD 2.02) for NSCLC, 73.31 (SD 1.11) versus 67.96 (SD 2.15) for breast cancer, and 61.57 (SD 0.09) versus 60.08 (SD 0.17) for diabetes (DT); 85.61 (SD 0.29) versus 79.01 (SD 1.20) for NSCLC, 78.05 (SD 1.59) versus 73.48 (SD 4.73) for breast cancer, and 59.98 (SD 0.24) versus 58.55 (SD 0.17) for diabetes (RF); 85.20 (SD 0.82) versus 76.42 (SD 0.93) for NSCLC, 77.86 (SD 2.27) versus 68.32 (SD 2.37) for breast cancer, and 60.18 (SD 0.20) versus 58.98 (SD 0.29) for diabetes (XGBoost); and 85.14 (SD 0.77) versus 77.62 (SD 1.85) for NSCLC, 78.16 (SD 1.52) versus 70.02 (SD 2.17) for breast cancer, and 61.75 (SD 0.13) versus 61.12 (SD 0.23) for diabetes (LGBM). In addition, we found that balanced synthetic data performed better. CONCLUSIONS: This study is the first attempt to generate and validate STD based on a DC approach and shows improved performance using STD. The necessity for balanced SDG was also demonstrated.

Effects of ranitidine and nizatidine on the risk of gastrointestinal cancer.

Purpose: Gastrointestinal (GI) cancer occurs in digestive organs such as the stomach, colon, liver, esophagus, and pancreas. About 83,034 cases occurred in Korea alone in 2020. Dietary factors, alcohol consumption, Helicobacter pylori (H. pylori), and lifestyle factors increase the incidence of diseases such as gastritis, peptic ulcer, pancreatitis, and gastroesophageal reflux disease (GERD), which can develop into GI cancer. However, in 2019, the US Food and Drug Administration announced that the drugs ranitidine and nizatidine, which are used for digestive disorders, contain carcinogens. In this study, we investigated the effects of ranitidine and nizatidine on the development of GI cancer. Materials and methods: In this study, using National Health Insurance Service-National Sample Cohort (NHIS-NSC) version 2.5 (updated from 2002 to 2019), subjects who developed GI cancer were enrolled in the case group, and those who were at risk of, but did not develop, cancer were enrolled in the control group. Thereafter, risk-set matching was performed (1:3 ratio) by sex and age at the time of diagnosis of cancer in the case group. Through this procedure, 22,931 cases and 68,793 controls were identified. The associations of ranitidine and/or nizatidine with GI cancer were confirmed by adjusted odds ratios (aORs) and 95% confidence intervals (CIs) calculated through conditional logistic regression analysis. Results: The aORs of ranitidine and/or nizatidine users were lower than those of nonusers in all average prescription days groups (< 30 days/year: aOR [95% CI] = 0.79 [0.75-0.82]; 30-59 days/year: aOR [95% CI] = 0.66 [0.59-0.73]; 60-89 days/year: aOR [95% CI] = 0.69 [0.59-0.81]; ≥ 90 days/year: aOR [95% CI] = 0.69 [0.59-0.79]). Sensitivity analyses were conducted with different lag periods for the onset of GI cancer after drug administration, and these analyses yielded consistent results. Additional analyses were also performed by dividing subjects into groups based on cancer types and CCI scores, and these analyses produced the same results. Conclusion: Our study, using nationwide retrospective cohort data, did not find evidence suggesting that ranitidine and nizatidine increase the risk of GI cancer. In fact, we observed that the incidence of GI cancer was lower in individuals who used the drugs compared to nonusers. These findings suggest a potential beneficial effect of these drugs on cancer risk, likely attributed to their ability to improve digestive function.

The effects of hospice care on healthcare expenditure among cancer patients.

PURPOSE: It is necessary to estimate the hospice usage and hospice-related cost for entire cancer patients using nationwide cohort data to establish a suitable ethical and cultural infrastructure. This study aims to show the effects of hospital hospice care on healthcare expenditure among South Korean cancer patients. METHODS: This study is a retrospective cohort study using customized health information data provided by the National Health Insurance Service. Individuals who were diagnosed with stomach, colorectal, or lung cancer between 2003 and 2012 were defined as new cancer patients, which included 7,176 subjects. Patients who died under hospital-based hospice care during the follow-up period from January 2016 to December 2018 comprised the treatment group. Healthcare expenditure was the dependent variable. Generalized estimating equations was used. RESULTS: Among the subjects, 2,219 (30.9%) had used hospice care at an average total cost of 948,771 (± 3,417,384) won. Individuals who had used hospice care had a lower odds ratio (EXP(ß)) of healthcare expenditure than those who did not (Total cost: EXP(ß) = 0.27, 95% confidence intervals (CI) = 0.25-0.30; Hospitalization cost: EXP(ß) = 0.32, 95% CI = 0.29-0.35; Outpatient cost: EXP(ß) = 0.02, 95% CI = 0.02-0.02). CONCLUSION: Healthcare expenditure was reduced among those cancer patients in South Korea who used hospice care compared with among those who did not. This emphasizes the importance of using hospice care and encourages those hesitant to use hospice care. The results provide useful insights into both official policy and the existing practices of healthcare systems.

Cancer care patterns in South Korea: Types of hospital where patients receive care and outcomes using national health insurance claims data.

BACKGROUND: Although strengthening coverage has improved cancer care, there are concerns related to medical distortion. Previous studies have only examined whether patients visit a specific hospital, and not the continuum of patients with cancer, resulting in a lack of evidence in South Korea. This study aimed to investigate the patterns in hospital type for cancer care and analyze their association with outcomes. METHODS: The data for this study were obtained from the National Health Insurance Services Sampled Cohort database. This study included patients with four types of cancer (top four cancer incidence in 2020): gastric (3353), colorectal (2915), lung (1351), and thyroid (5158) cancer. The latent class mixed model was used to investigate cancer care patterns, and multiple regression or survival analysis was performed to examine medical cost, length of stay (LOS), and mortality. RESULTS: The patterns in each cancer type were classified into two to four classes, namely, mainly visited clinics or hospitals, mainly visited general hospitals, mainly visited tertiary hospitals (MT), and tertiary to general hospitals through trajectory modeling based on the utilization of cancer care. Compared to the MT pattern, other patterns were generally associated with higher cost, LOS, and mortality. CONCLUSION: The patterns found in this study may be a more realistic way of defining patients with cancer in South Korea compared to previous studies, and its association-related outcomes may be used as a basis to address problems in the healthcare system and prepare alternatives for patients with cancer. Future studies should review cancer care patterns related to other factors such as regional distribution.

Association of polypharmacy with all-cause mortality and adverse events among elderly colorectal cancer survivors.

BACKGROUND: The risk of inappropriate drug exposure in elderly colorectal cancer (CRC) survivors after the initial cancer treatment has not been well studied. This study investigated the association of polypharmacy (PP) with overall survival, hospitalization, and emergency room (ER) visits among older CRC survivors. METHODS: A retrospective cohort study was conducted using the Korean National Health Insurance claims data follow-up from 2002 to 2017. Participants comprised those aged ≥65 years who were hospitalized with a diagnosis of CRC received cancer treatment and survived at least 2 years from the initial CRC diagnosis between 2003 and 2012. PP was defined based on the number of individual drugs during the third year, after 2 years of survival since the initial cancer treatment. PP was categorized as follows: non-PP (zero to four prescribed drugs); PP (five to nine drugs), and excessive PP (≥10 drugs). Main outcomes are all-cause mortality, hospitalization, and ER visits. RESULTS: Of the 55,228 participants, 44.5% died, 83.1% were hospitalized, and 46.1% visited the ER. The PP and excess PP groups showed increased risk of all-cause mortality, hospitalization, and ER visit compared with the low PP group, and was highly associated among groups including patients aged 65 to 74 years and those in low-level frailty groups. CONCLUSIONS: These risks can be minimized by increasing awareness and enhancing behaviors among health care professionals, especially clinician and pharmacists, to be aware of potential drug interactions, review, and ongoing monitoring. PLAIN LANGUAGE SUMMARY: The risk of inappropriate drug exposure in older colorectal cancer (CRC) survivors after the initial cancer treatment has not been well studied. Polypharmacy was associated with adverse outcomes, including all-cause mortality, hospitalization, and emergency room visits among older CRC survivors and it was particularly associated with those who were 65 to 75 years and those with low risk of frailty. When prescribing drugs, physicians should be mindful of finding a balance between adequate treatment of diseases and avoiding adverse drug effects in survivors of CRC.

Does fragmented cancer care affect survival? Analysis of gastric cancer patients using national insurance claim data.

BACKGROUND: We aimed to investigate the association between fragmented cancer care in the early phase after cancer diagnosis and patient outcomes using national insurance claim data. METHODS: From a nationwide sampled cohort database, we identified National Health Insurance beneficiaries diagnosed with gastric cancer (ICD-10: C16) in South Korea during 2005-2013. We analyzed the results of a multiple logistic regression analysis using the generalized estimated equation model to investigate which patient and institution characteristics affected fragmented cancer care during the first year after diagnosis. Then, survival analysis using the Cox proportional hazard model was conducted to investigate the association between fragmented cancer care and five-year mortality. RESULTS: Of 2879 gastric cancer patients, 11.9% received fragmented cancer care by changing their most visited medical institution during the first year after diagnosis. We found that patients with fragmented cancer care had a higher risk of five-year mortality (HR: 1.310, 95% CI: 1.023-1.677). This association was evident among patients who only received chemotherapy or radiotherapy (HR: 1.633, 95% CI: 1.005-2.654). CONCLUSIONS: Fragmented cancer care was associated with increased risk of five-year mortality. Additionally, changes in the most visited medical institution occurred more frequently in either patients with severe conditions or patients who mainly visited smaller medical institutions. Further study is warranted to confirm these findings and examine a causal relationship between fragmented cancer care and survival.

Benefit and risk of prolonged dual antiplatelet therapy after drug-eluting stent implantation in patients with chronic kidney disease: A nationwide cohort study.

BACKGROUND AND AIMS: The optimal duration of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) with drug-eluting stent in patients with chronic kidney disease (CKD) is not clearly established. This study purposed to compare clinical outcomes of patients with 6-12 (standard) versus 12-24 months (prolonged) DAPT according to CKD. METHODS: Using a nationwide, claim-based database, we retrospectively evaluated association between DAPT duration and clinical outcomes including death, composite ischemic event, and composite bleeding event between 1 and 3 years after PCI. CKD was defined as estimated glomerular filtration rate <60 mL/min/1.73 m2. Of 73,941 eligible patients, 13,425 (18.2%) had CKD and 49,019 (66%) were prescribed prolonged DAPT. Prolonged DAPT had no significant impact on the risk of clinical outcomes in patients with normal renal function. RESULTS: In patients with CKD, prolonged DAPT was associated with a lower risk of all-cause death (HR 0.85, 95% CI 0.76-0.95) and composite ischemic events (HR 0.87, 95% CI 0.78-0.96) and a higher risk of composite bleeding events (HR 1.18, 95% CI 1.02-1.37). Benefit of prolonged DAPT on reducing composite ischemic event increased significantly in patients with worsened renal dysfunction (pinteraction = 0.02) while there was no significant interaction between its bleeding risk and renal dysfunction (pinteraction = 0.22). CONCLUSIONS: While standard DAPT would be recommended in patients with normal renal function, tailored decision for DAPT duration would be considered in those with CKD to balance between ischemic and bleeding risks.

Fragmentation of care and colorectal cancer survival in South Korea: comparisons according to treatment at multiple hospitals.

PURPOSE: Fragmented cancer care (FC) means that patients visit multiple providers for treatment, which is common in cancer care. While FC is associated with poor health outcomes in patients with colorectal cancer (CRC) worldwide, there is still a lack of evidence in South Korea. We investigated the association between FC and 5-year morality in patients with CRC using population-based claims data. METHODS: The study population was followed up from 2002 to 2015. Data were collected from Korea National Health Insurance claims. Participants comprised patients with CRC diagnosed with International Classification of Diseases (ICD)-10 (C18.x-C20.x) and a special claim code for cancer (V193). Data were analyzed using the Kaplan-Meier curve with a log-rank test and Cox proportional hazard model. The effect of FC on patients' 5-year survival was examined. RESULTS: Of 3467 patients with CRC, 20.0% had experienced FC. FC was significantly associated with an increased risk of 5-year mortality (hazard ratio 1.516, 95% confidence interval 1.274-1.804). FC was prevalent in those who had a low income level, underwent chemotherapy, did not undergo radiation therapy, and did not visit a tertiary hospital for their first treatment. CONCLUSION: Efforts to decrease FC and integrate complex cancer care within appropriate healthcare delivery systems may improve survivorship among patients with CRC.

Association of institutional transition of cancer care with mortality in elderly patients with lung cancer: a retrospective cohort study using national claim data.

BACKGROUND: Although survival based outcomes of lung cancer patients have been well developed, institutional transition of cancer care, that is, when patients transfer from primary visiting hospitals to other hospitals, and mortality have not yet been explored using a large-scale representative population-based sample. METHODS: Data from the Korean National Elderly Sampled Cohort survey were used to identify patients with lung cancer who were diagnosed during 2005-2013 and followed up with for at least 1 year after diagnosis (3738 patients with lung cancer aged over 60 years). First, the authors examined the distribution of the study population by mortality, and Kaplan-Meier survival curves/log-rank test were used to compare mortality based on institutional transition of cancer care. Survival analysis using the Cox proportional hazard model was conducted after controlling for all other variables. RESULTS: Results showed that 1-year mortality was higher in patients who underwent institutional transition of cancer care during 30 days after diagnosis (44.2% vs. 39.7%, p = .027); however, this was not associated with 5-year mortality. The Cox proportional hazard model showed that patients who underwent institutional transition of cancer care during 30 days after diagnosis exhibited statistically significant associations with high mortality for 1 year and 5 years (1-year mortality, Hazard ratio [HR]: 1.279, p = .001; 5-year mortality, HR: 1.158, p = .002). CONCLUSION: This study found that institutional transition of cancer care was associated with higher mortality among elderly patients with lung cancer. Future consideration should also be given to the limitation of patients' choice when opting for institutional transition of care since there are currently no control mechanisms in this regard. Results of this study merit health policymakers' attention.

Disparities in diabetes-related avoidable hospitalization among diabetes patients with disability using a nationwide cohort study.

Diabetes is an ambulatory care sensitive condition that quality of care can prevent complications development and hospitalization needs. However, diabetes patients with disability face greater challenges with receiving quality diabetes care than those without disabilities. This study examined diabetes-related avoidable hospitalizations (DRAH) focusing on the association with disability. We used nationally representative health insurance cohort data from 2002 to 2013. The study population is people who were newly diagnosed with type 2 diabetes. We measured the cumulated number of DRAH using the Prevention Quality Indicators (PQIs). The variables of interest were disability severity and type. We performed a recurrent events analysis using Cox proportional hazard regression model. Among 49,410 type 2 diabetes patients, 12,231 (24.8%) experienced DRAHs at least once during the follow-up period. Among the total population, 5924 (12.0%) diabetes patients were registered as disabled. The findings report that disability severity was significantly associated with higher risks for DRAH, where severely disabled diabetes patients showed the highest hazard ratio of 2.24 (95% CI 1.80-2.79). Among three DRAH indicators, severely disabled diabetes patients showed increased risks for long-term (AHR 2.21, 95% CI 1.89-2.60) and uncontrolled (AHR 2.28, 95% CI 1.80-2.88) DRAH. In addition, intellectual (AHR 5.52, 95% CI 3.78-8.05) and mental (AHR 3.97, 95% CI 2.29-6.89) disability showed higher risks than other types of disability. In conclusion, diabetes patients with disability are at higher risk for DRAH compared to those without disabilities, and those with intellectual and mental disabilities were more likely to experience DRAH compared to those with physical or other types of disability. These findings call for action to find the more appropriate interventions to improve targeted diabetes primary care for patients with disability. Further research is needed to better understand determinants of increasing risks of DRAH.

Increasing disparities in the proportions of active treatment and 5-year overall survival over time by age groups among older patients with gastric cancer in Korea.

Purpose: As older patients with gastric cancer increase in Korea, no consensus indicative of anti-cancer treatment exists for the oldest old (age 85+). We investigated potential disparities in the proportion of surgery-including active treatment and the degree of survival improvement over time by age groups, and whether heterogeneity exists in the protective effect of time period on overall survival (OS) by age at diagnosis clusters. Materials and methods: A nationwide cohort (N = 63,975) of older patients with gastric cancer (age at diagnosis 70+) in 2005-2012 were followed until the end of 2018. Patients were categorized into four time period groups by their year of diagnosis. Cancer treatment patterns and 5-year OS were analyzed accordingly, and a random coefficients Cox model with random intercepts and random slopes of time period by age at diagnosis clusters was employed. Results: The mean age of patients was 76.4, and 60.4% were males. Most patients had 0-1 comorbidities (73.3%) and low-risk frailty scores (74.2%). Roughly two-thirds of patients received some form of anti-cancer treatment (62.4%), and while the number of comorbidities and the proportion of high-risk frailty scores trended toward an increase, the proportion of patients receiving anti-cancer treatment increased from 58% in 2005-2006 to 69.6% in 2011-2012. The proportion of surgery-including active treatment increased to over 70% in the 70-74 years old group, while stagnating at 10% in the 90+ years old group. Differences in the slope of 5-year OS improvement resulted in a widening survival gap between the old (age 70-84) and the oldest old. The protective effect of time period on OS hazard in the oldest old was not monotonically reduced with increasing "chronological" age but varied quite randomly, especially among female patients. Conclusion: Our study showed no upper age limit in terms of benefiting from the advances in the detection and treatment of gastric cancer over time. Thus, "functional" age rather than "chronological" age should be the criterion for anti-cancer screening and treatment, and actual implementation of proven treatments in the oldest old patients to reduce their non-compliance with treatment in clinical practice is needed to improve gastric cancer survival for all.

A comprehensive study of deaths due to exposure to humidifier disinfectant in Korea: focusing on medical records, assessment of exposure to humidifier disinfectants, and causes of death.

OBJECTIVES: We aimed to determine the characteristics of the deceased victims of deaths caused by exposure to humidifier disinfectants, and present the distribution of the victims' data submitted for damage application, demographic characteristics, imaging findings, characteristics of humidifier disinfectant exposure, and distribution of the causes of death. METHODS: An integrated database of victims was established using the medical records data of 1,413 victims submitted during the application for death damage caused by exposure to humidifier disinfectants, and the demographic characteristics, medical records, imaging findings, exposure characteristics, and cause of death were examined. RESULTS: The average numbers of data submissions of each applicant for death damage were 3.0 medical use records. A total of 608 (43.0%) victims had more than one finding of acute, subacute, or chronic interstitial lung diseases. The average daily and cumulative use times of the victims were 14.40 and 24,645.81 hours, respectively, indicating greater exposure in this group than in the survivors. The humidifier disinfectants' components comprised polyhexamethylene guanidine (72.8%), chloromethylisothiazolinone/methylisothiazolinone (10.5%), other components (15.0%), and oligo-[2-(2-ethoxy)-ethoxyethyl] guanidine chloride (1.5%). The components' distribution was 67.8% for single-component use, which was higher than that in the survivors (59.8%). The distribution of the causes of death were: respiratory diseases (54.4%), neoplasms (16.8%), and circulatory diseases (6.3%). Other interstitial lung diseases (65.5%) were the most common cause of death among those who died due to respiratory diseases. CONCLUSIONS: Careful discussions of appropriate remedies should be conducted based on a comprehensive understanding of the characteristics of the deceased victims, considering their specificities and limitations.

Pioglitazone use associated with reduced risk of the first attack of ischemic stroke in patients with newly onset type 2 diabetes: a nationwide nested case-control study.

BACKGROUND: Pioglitazone use is known to be associated with a reduced risk of recurrent stroke in patients with diabetes mellitus (DM) who have a history of stroke. However, it is unclear whether this benefit extends to patients without a history of stroke. We aimed to evaluate the association between pioglitazone use and development of first attack of ischemic stroke in patients with newly diagnosed type 2 DM. METHODS: Using longitudinal nationwide data from the 2002-2017 Korean National Health Insurance Service DM cohort, we analyzed the association between pioglitazone use and incidence of primary ischemic stroke using a nested case-control study. Among 128,171 patients with newly onset type 2 DM who were stroke-free at the time of DM diagnosis, 4796 cases of ischemic stroke were identified and matched to 23,980 controls based on age, sex, and the onset and duration of DM. The mean (standard deviation) follow-up time was 6.08 (3.34) years for the cases and controls. Odds ratios (ORs) and 95% confidence intervals (CIs) for the association between ischemic stroke and pioglitazone use were analyzed by multivariable conditional logistic regression analyses adjusted for comorbidities, cardiometabolic risk profile, and other oral antidiabetic medications. RESULTS: Pioglitazone use was associated with a reduced risk of first attack of ischemic stroke (adjusted OR [AOR] 0.69, 95% CI 0.60-0.80) when compared with non-use. Notably, pioglitazone use was found to have a dose-dependent association with reduced rate of ischemic stroke emergence (first cumulative defined daily dose [cDDD] quartile AOR 0.99, 95% CI 0.74-1.32; second quartile, AOR 0.77, 95% CI 0.56-1.06; third quartile, AOR 0.51, 95% Cl 0.36-0.71; highest quartile, AOR 0.48, 95% CI 0.33-0.69). More pronounced risk reduction was found in patients who used pioglitazone for more than 2 years. A further stratified analysis revealed that pioglitazone use had greater protective effects in patients with risk factors for stroke, such as high blood pressure, obesity, and current smoking. CONCLUSIONS: Pioglitazone use may have a preventive effect on primary ischemic stroke in patients with type 2 DM, particularly in those at high risk of stroke.

Is time-to-treatment associated with higher mortality in Korean elderly lung cancer patients?

Lung cancer is a leading cause of cancer-related deaths in many countries, including South Korea. As treatment delays after diagnosis may correlate with survival, this study aimed to investigate the association between time-to-treatment and one-and five-year overall mortality in patients aged 60 years or above. Survival analysis using the Cox proportional hazard model were conducted after controlling for all independent variables. Of a total of 1,535 individuals who received surgical treatment due to lung cancer, 837 patients received treatment within 30 days and 698 after 30 days of initial diagnosis. Individuals who received surgical treatment after 30 days of diagnosis were more likely to die within 1-year (Hazard Ratio, HR: 1.15, 95% Confidence Interval, CI: 1.01-1.32) and 5-year (HR: 1.16, 95% CI: 1.02-1.33) compared to those who received treatment within 30 days. The increase in mortality risk with time delay persisted when applying other cut-off times, including standards at 2, 3, and 6 months. We also found that the mortality rate of lung cancer patients differs depending on age (74 years or younger), household income (<80 percentile), patient severity, and the residing region. Our findings show that time delay is an important factor that can influence the outcome of lung cancer patients, highlighting the importance of monitoring and providing appropriate and timely treatment.

The effect of shifting medical coverage from National Health Insurance to Medical Aid type I and type II on health care utilization and out-of-pocket spending in South Korea.

BACKGROUND: This study examines the effects of a shift in medical coverage, from National Health Insurance (NHI) to Medical Aid (MA), on health care utilization (measured by the number of outpatient visits and length of stay; LOS) and out-of-pocket medical expenses. METHODS: Data were collected from the Korean Welfare Panel Study (2010-2016). A total of 888 MA Type I beneficiaries and 221 MA Type II beneficiaries who shifted from the NHI were included as the case group and 2664 and 663 consecutive NHI holders (1:3 propensity score-matched) were included as the control group, respectively. We used the 'difference-in-differences' (DiD) analysis approach to assess changes in health care utilization and medical spending by the group members. RESULTS: Differential average changes in outpatient visits in the MA Type I panel between the pre- and post-shift periods were significant, but differential changes in LOS were not found. Those who shifted from NHI to MA Type I had increased number of outpatient visits without changes in out-of-pocket spending, compared to consecutive NHI holder who had similar characteristics. However, this was not found for MA Type II beneficiaries. CONCLUSION: Our research provides evidence that the shift in medical coverage from NHI to MA Type I increased the number of outpatient visits without increasing the out-of-pocket spending. Considering the problem of excess medical utilization by Korean MA Type I beneficiaries, further researches are required to have in-depth discussions on the appropriateness of the current cost-sharing level on MA beneficiaries.

Association between change in lifestyle and cognitive functions among elderly Koreans: findings from the Korean longitudinal study of aging (2006-2016).

BACKGROUND: South Korea is an aged society that continues to age rapidly. Therefore, the purpose of this study was to investigate the association between changes in lifestyle and cognitive functions in the South Korean elderly using a nationally representative survey. METHODS: We analyzed data from the Korean Longitudinal Study of Aging (KLoSA) 2006-2016, a biannual panel survey. Multiple linear regression analysis was performed with repeated measurements data to examine the association between lifestyle change and cognitive functions over 2 years. Lifestyle combined the scores of four factors (smoking status, alcohol drinking status, body weight, and exercise), and then categorized them into four groups (Good→Good, Bad→Good, Good→Bad, and Bad→Bad) according to the two-year change. Cognitive functions were set according to the scores measured through the Korean Mini-Mental State Examination (K-MMSE). RESULTS: Among females, the K-MMSE score was the highest in the Bad→Good group compared to the reference group, Bad→Bad (ß = 0.914; SD = 3.744; p < .0001). The next highest scores were in the Good→Good group (ß = 0.813; SD = 4.654; p = 0.0005) and the Good→Bad group (ß = 0.475; SD = 4.542; p = 0.0481). Among males, only the K-MMSE of the Good→Good group was statistically significant (ß = 0.509; SD = 3.245; p = 0.0077). The results of subgroup analysis showed that the K-MMSE scores of females who did not participate in any social activities were more affected by their lifestyle (Good-Good: ß = 1.614; SD = 4.270; p = 0.0017, Bad-Good: ß = 1.817; SD = 3.945; p < .0001). Subgroup analysis showed that females who started drinking more than a moderate amount of alcohol had lower K-MMSE scores (Good-Bad: ß = - 2.636; SD = 2.915; p = 0.0011). Additionally, in both sexes, exercising, among the four lifestyle options, had a strong and significant association with higher K-MMSE scores. CONCLUSIONS: Following a healthy lifestyle or improving an unhealthy lifestyle can help people prevent or slow down cognitive decline. Regularly engaging in an adequate amount of exercise can help the cognitive function of the elderly. Females, specifically, can experience positive effects on their cognitive function if they participate in social activities while maintaining healthy lifestyles, in particular not drinking too much alcohol.

Annual Disease Experience by Type and Correlations with Unmet Healthcare Needs among ROK Military Personnel.

INTRODUCTION: The National Statistical Yearbook of Defense 2018 issued by the Republic of Korea (ROK) Ministry of National Defense reported that the number of patients using military hospitals steadily increased from 2008 to 2017. However, in the outpatient clinic statistics for years 2015-2017 from the ROK Armed Forces Medical Command, the amount of medical care received from some medical departments, such as the infection medicine, surgery, and anesthesiology departments, decreased. Therefore, the purpose of this study was to observe the differences in incidence of military personnel's unmet healthcare needs according to number of diseases by type. MATERIALS AND METHODS: The study used data from the Military Health Survey, which was conducted from 2014 to 2015 and included 5162 responses from ROK military personnel. The number of diseases by type and unmet healthcare needs were self-reported. A multiple logistic regression analysis was used to examine the validity of the annual disease experience by type and correlations with unmet healthcare needs. RESULTS: Of the 5162 military personnel, 25.2% experienced unmet healthcare needs, and the more people with the number of disease by type, the more likely they were to experience unmet healthcare needs (1: 13.4%, 2: 22.9%, 3: 29.2%, 4: 34.5%, 5: 41.4%). The logistic regression analysis also revealed significant differences (1 = REF, 2 odds ratio (OR) = 1.83, 95% confidence interval (CI): 1.50-2.24; 3 OR = 2.53, 95% CI: 2.05-3.11, 4 OR = 3.10, 95% CI = 2.49-3.85; ≥5 OR = 3.85, 95% CI = 3.08-4.81). In addition, subgroup analysis showed that female military personnel are more likely to experience unmet healthcare needs than are male military personnel. We have also confirmed that working areas and private insurance can affect unmet healthcare needs. CONCLUSION: This study suggests that unmet healthcare needs are influenced by the number of disease by the type of ROK military personnel. It is therefore necessary to strive to reduce the number of military personnel who experience unmet healthcare needs through this data.