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Background and Objectives: The ongoing coronavirus disease 2019 (COVID-19) pandemic represents a global public health crisis that has had a serious impact on emergency department (ED) utilization trends. The aim of this study was to investigate the collateral effects of the COVID-19 pandemic on ED utilization trends by patients with mild and severe conditions as well as on 7-day fatality rates. Materials and Methods: We analyzed entries in the Korean National Health Insurance claims database between 1 January 2018 and 31 December 2020. Six target patient groups were identified using the main diagnosis codes in the 10th revision of the International Classification of Diseases. Numbers of patients visiting the ED, their age, regional differences, 7-day fatality rate, and rate of emergency procedures were compared between 2018 and 2019 as the control period and 2020, when the COVID-19 pandemic was in full force. Results: During the 2020 COVID-19 pandemic, the number of patients who visited the ED with low-acuity diseases and severe acute respiratory infection diseases sharply decreased to −46.22% and −56.05%, respectively. However, the 7-day fatality rate after ED visits for low-acuity diseases and severe acute respiratory infection diseases increased to 0.04% (p < 0.01), and 1.65% (p < 0.01), respectively, in 2020 compared to that in the control period. Conclusions: During the 2020 COVID-19 pandemic, ED utilization impacted and 7-day fatality rate after ED visit increased. Health authorities and health care providers must strive to ensure prompt delivery of optimal care in EDs for patients with severe or serious symptoms and time-dependent diseases, even during the ongoing COVID-19 or potential future pandemics.

Objectives: Clinical manifestations of lipoid pneumonia (LP) vary depending on the causative agents or underlying causes. The aim of the present study was to investigate the clinical and radiological features of LP, classified according to etiologic agents., Methods: The clinico-radiological characteristics of LP patients were retrospectively compared among groups: exogenous versus idiopathic and squalene versus omega-3-acid ethyl esters (O-3-AEE) versus idiopathic. Idiopathic group was defined as LP with no proven or reported etiological evidence., Results: Twenty-two patients met the diagnostic criteria for LP: squalene (9 [41%]), O-3-AEE (6 [27%]), olive oil (1 [5%]), and idiopathic (7 [32%]). Compared with the exogenous group, the idiopathic group showed a higher recurrence rate; higher frequencies of bronchial anthracofibrosis (BAF) and bronchoalveolar lavage (BAL) lymphocytosis; and a higher rate of crazy-paving pattern and lower rate of consolidation on computed tomography scan. In three-group tests, compared with the O-3-AEE group, the squalene group exhibited a significantly higher percentage of neutrophils and a higher rate of right middle lobe (RML) involvement., Conclusions: In comparison with the exogenous group, the idiopathic group demonstrated BAL lymphocytosis, higher rates of recurrence and BAF, and a higher rate of crazy-paving pattern. Compared with the O-3-AEE group, the squlaene group showed a higher percentage of BAL neutrophils and predominant RML involvement., (© 2019 John Wiley & Sons Ltd.)

We evaluated the associations between potentially functional variants in a comprehensive list of cancer-related genes and lung cancer in a Korean population.A total of 1969 potentially functional single nucleotide polymorphisms (SNPs) of 1151 genes involved in carcinogenesis were evaluated using an Affymetrix custom-made GeneChip in 610 nonsmall cell lung cancer patients and 610 healthy controls. A replication study was conducted in an independent set of 490 cases and 486 controls. 68 SNPs were significantly associated with lung cancer in the discovery set and tested for replication.Among the 68 SNPs, three SNPs (corepressor interacting with RBPJ 1 (CIR1) rs13009079T>C, ribonucleotide reductase M1 (RRM1) rs1465952T>C and solute carrier family 38, member 4 (SLC38A4) rs2429467C>T) consistantly showed significant associations with lung cancer in the replication study. In combined analysis, adjusted odds ratio for CIR1 rs13009079T>C, RRM1 rs1465952T>C and SLC38A4 rs2429467C>T were 0.69, 0.71 and 0.73, respectively (p=4×10 -5 , 0.01 and 0.001, respectively) under the dominant model. The relative mRNA expression level of CIR1 was significantly associated with rs13009079T>C genotypes in normal lung tissues (p trend =0.03).These results suggest that the three SNPs, particularly CIR1 rs13009079T>C, may play a role in the pathogenesis of lung cancer., (Copyright ©ERS 2016.)

Recently, genetic variants in the WNT signaling pathway have been reported to affect the survival outcome of Caucasian patients with early stage non-small cell lung cancer (NSCLC). We therefore attempted to determine whether these same WNT signaling pathway gene variants had similar impacts on the survival outcome of NSCLC patients in a Korean population. A total of 761 patients with stages I-IIIA NSCLC were enrolled in this study. Eight variants of WNT pathway genes were genotyped and their association with overall survival and disease-free survival were analyzed. None of the eight variants were significantly associated with overall survival or disease-free survival. There were no differences in survival outcome after stratifying the subjects according to age, gender, smoking status, and histological type. These results suggest that genetic variants in the WNT signaling pathway may not affect the survival outcome of NSCLC in a Korean population.

Objectives: Tuberculous pleural effusion (TPE) is generally characterized by lymphocytic exudative effusion, either free-flowing or loculated. However, patients can also have neutrophilic loculated TPE, although little data are available concerning the incidence and characteristics of this form of TPE. It is important to differentiate between neutrophilic loculated TPE and complicated parapneumonic effusion (PPE), which also shows neutrophilic loculated effusion but needs a different management approach. The present study evaluated the incidence and characteristics of neutrophilic loculated TPE and differentiated it from complicated PPE., Materials and Methods: Between 2009 and 2014, a cohort of patients with TPE was retrospectively reviewed in a South Korean referral hospital. Clinical, laboratory, computed tomography and pleural fluid findings of patients with neutrophilic loculated TPE were compared to those of patients with neutrophilic free-flowing TPE and complicated PPE, respectively., Results: Neutrophilic TPE was observed in 33 (10%) out of 344 patients with TPE. Of these, 10 (30%) patients exhibited loculation of the pleural fluid. These patients showed distinct pleural fluid characteristics. The classical pleural fluid biomarker levels were more intense than those observed in 23 patients with neutrophilic free-flowing TPE, but similar to those of 54 patients with complicated PPE. A high mycobacterial burden was observed in the pleural fluid, and favorable outcomes were achieved with antituberculosis drug administration alone. Nodular parenchymal lesions and pleural fluid adenosine deaminase levels were independent discriminators of neutrophilic loculated TPE and PPE., Conclusions: These results may be helpful to understand and manage patients with neutrophilic loculated TPE and differentiate them from patients with complicated PPE., (Copyright © 2016 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.)

Short telomeres are known as one of the risk factors for human cancers. The present study was conducted to evaluate the association between 6 polymorphisms, which were related with short telomere length in the Korean population, and lung cancer risk using 1,100 cases and 1,096 controls. Among the 6 polymorphisms, TERT rs2853669 was significantly associated with increased lung cancer risk under a recessive model (odds ratio [OR]=1.38, 95% confidence interval [CI]=1.05-1.81, P=0.02). The effect of rs2853669 on lung cancer risk was significant in younger individuals (OR=1.73, 95% CI=1.18-2.54, P=0.005) and adenocarcinoma (OR=1.50, 95% CI=1.07-2.07, P=0.02). Our results suggest that a common functional promoter polymorphism, TERT rs2853669, may influence both telomere length and lung cancer risk in the Korean population.

We searched for potential regulatory single nucleotide polymorphisms (SNPs) in excision repair cross-complementing group 1 (ERCC1) using RegulomeDB, a database integrating information from the Encyclopedia of DNA Elements (ENCODE) project, and investigated their association with survival after surgery in non-small cell lung cancer (NSCLC). Among 364 SNPs found within ERCC1 region using RegulomeDB, four top priority SNPs (rs2298881C>A, rs1049739A>G, rs10415949A>G and rs6509214G>T) were selected for this study. The four SNPs were investigated in 316 patients. A replication study was performed (n = 579). Of the four SNPs analyzed in the discovery set, rs2298881C>A and rs6509214G>T were significantly associated with survival outcomes. The association was consistently observed only for rs2298881C>A in the validation cohort. In combined analysis, rs2298881C>A was significantly associated with worse overall survival and disease-free survival (P = 0.0002 and 0.02, respectively). A decreased reporter gene expression for rs2298881 A allele was observed compared with C allele by luciferase assay (P = 0.02). ERCC1 rs2298881C>A, an intronic SNP, is the first genetic polymorphism with functional evidence of regulating its expression, and the SNP is associated with prognosis of NSCLC. Our result supports the role of RegulomeDB as a comprehensive source of prioritized candidate SNPs for genetic association studies.

Background/aims: A number of genome-wide and candidate gene association studies have identified polymorphisms associated with telomere length in Caucasian populations. This study was conducted to determine the impacts of 17 polymorphisms identified in Caucasians on telomere length in a Korean population., Methods: Ninety-four healthy individuals were enrolled in this study. Relative telomere length of chromosomes from peripheral blood samples was measured using quantitative polymerase chain reaction., Results: Two polymorphisms, rs10936599 of MYNN and rs412658 of ZNF676, were found to be associated w ith telomere length (under dominant model, p = 0.04; under recessive model, p = 0.001). Three polymorphisms, rs2853669, rs7705526, and rs2736108, at the TERT locus were also associated with telomere length (under recessive model, p = 0.01, p = 0.02, and p = 0.01, respectively). The genotypes of the five polymorphisms associated with short telomere length were considered bad genotypes; telomere length was significantly decreased with increasing number of bad genotypes (p= 1.7 × 10(-5))., Conclusions: We have identified polymorphisms associated with telomere length in a Korean population.

The Encyclopedia of DNA elements (ENCODE) project revealed that nearby or distantly located non-coding DNA regulates the expression of coding genes. RegulomeDB (http://regulome.stanford.edu) is a new database that can be used to predict whether a variant affects transcription factor binding and gene expression. We investigated the association between lung cancer risk and potentially functional polymorphisms of XRCC1 that were selected using RegulomeDB in a Korean population. A total of 185 polymorphisms of XRCC1 were evaluated using RegulomeDB. Strong evidence suggested that 10 polymorphisms, from among the 185, affected XRCC1 expression with scores of 1a-1f that were based on the RegulomeDB scoring system. The rs2854510 polymorphism was rare in Asians (minor allele frequency < 0.05). Eight polymorphisms were in strong linkage disequilibrium (LD). The rs2854509 polymorphism, which was one of the 8 polymorphisms in LD, and rs7248167, which was not in the LD block, were genotyped in 610 lung cancer patients and 607 age- and sex-matched controls. Additionally, four polymorphisms of XRCC1 (rs25487, rs25489, rs1799782, and rs3213245), which were investigated with regard to their association with lung cancer risk in previous studies, were also genotyped. Two polymorphisms (rs2854509 and rs7248167) that were predicted to affect XRCC1 expression based on their RegulomeDB scores were not associated with lung cancer risk (P = 0.31 and 0.93, respectively). When stratified according to age, gender, smoking status, and tumor histology, the two polymorphisms of XRCC1 were not associated with lung cancer risk. Among the four polymorphisms that were previously studied, only rs25489 of XRCC1 was significantly associated with lung cancer risk (dominant model, adjusted odds ratio = 0.61, 95% confidence interval = 0.46-0.83, P = 0.002). Although RegulomeDB is an attractive tool for predicting the regulatory potential of variants, the two polymorphisms that were selected using RegulomeDB were not associated with lung cancer risk., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Recently, a genome-wide association study (GWAS) identified single nucleotide polymorphisms (SNPs) that may influence the prognosis of early-stage non-small cell lung cancer (NSCLC) in Caucasians. We attempted to replicate the impact of genetic variants identified in the GWAS on lung cancer survival in a Korean population. A total of 363 patients with surgically resected NSCLCs were enrolled, and 12 SNPs were genotyped using the SEQUENOM MassARRAY iPLEX assay, TaqMan assay, or a polymerase chain reaction-restriction fragment length polymorphism analysis. The association between genotypes and overall survival (OS) was analyzed. Among the 12 SNPs, the rs6034368T>C was associated with OS. Patients with the rs6034368C allele showed a better OS than the patients with the rs6034368T allele (adjusted hazard ratio = 0.72, confidence interval = 0.56-0.93, P = 0.01). The rs12446308A>G had an effect on OS, but it was marginally significant (under a codominant model, adjusted hazard ratio = 1.85, confidence interval = 0.98-3.47, P = 0.06). We identified that the rs6034368T>C was associated with survival in early-stage NSCLC in a Korean population., (Copyright © 2014. Published by Elsevier Inc.)

Background: Data concerning the rate of pulmonary embolism (PE) in Asian patients with chronic obstructive pulmonary disease (COPD) exacerbation are sparse, and no study has shown predictors of PE in these patients., Objectives: The purpose of the present study was to investigate the prevalence and predictors of PE in Korean patients with COPD exacerbation., Methods: Hospitalized patients with COPD exacerbations were prospectively enrolled into this study and underwent computed tomography (CT) pulmonary angiography and indirect CT venography., Results: The most common cause of COPD exacerbation was lower respiratory tract infection (82%; n = 84), followed by PE (5%; n = 5). Eight patients (8%) had venous thromboembolism, and deep vein thrombosis (DVT) was seen in 6%, with proximal DVT in 4%. On multivariate analysis, the absence of symptoms of respiratory infection and plasma D-dimer elevation (≥500 µg/l) were significant factors predicting PE in patients with COPD exacerbations (odds ratio 31, 95% confidence interval 2-563, p = 0.02, and odds ratio 25, 95% confidence interval 1-464, p = 0.03, respectively)., Conclusions: PE comprises approximately 5% of the etiologies of COPD exacerbations in Koreans. The absence of symptoms suggestive of respiratory infection and elevated plasma D-dimer levels were significant predictors of PE in this population., (Copyright © 2012 S. Karger AG, Basel.)

A genome-wide association study has identified the 15q25 region as being associated with the risk of chronic obstructive pulmonary disease (COPD) in Caucasians. This study intended as a confirmatory assessment of this association in a Korean population. The rs6495309C > T polymorphism in the promoter of nicotinic acetylcholine receptor alpha subunit 3 (CHRNA3) gene was investigated in a case-control study that consisted of 406 patients with COPD and 394 healthy control subjects. The rs6495309 CT or TT genotype was associated with a significantly decreased risk of COPD when compared to the rs6495309 CC genotype (adjusted odds ratio = 0.69, 95% confidence interval = 0.50-0.95, P = 0.023). The effect of the rs6495309C > T on the risk of COPD was more evident in moderate to very severe COPD than in mild COPD under a dominant model for the variant T allele (P = 0.024 for homogeneity). The CHRNA3 rs6495309C > T polymorphism on chromosome 15q25 is associated with the risk of COPD in a Korean population.

Background and Objective: Genome-wide association studies (GWAS) have identified the three chromosomal regions, 5p15, 6p21 and 15q25, as being associated with lung cancer risk in European populations. This study was performed to confirm these associations in Korean patients with lung cancer., Methods: The genotypes at rs2736100, rs402710, rs401681 and rs31489 at 5p15, rs9295740 at 6p22, which is in extensive linkage disequilibrium with the 6p21 region, as well as rs2036534 and rs6495309 at 15q25, were determined in 1094 patients with lung cancer and 1100 healthy control subjects, who were frequency matched for age and gender., Results: The single-nucleotide polymorphisms (SNP) at 5p15 (rs2736100, adjusted odds ratio [aOR] 1.32, 95% confidence interval [CI] 1.03-1.67, P = 0.025; rs402710, aOR 0.82, 95% CI 0.69-0.98, P = 0.025; rs401681, aOR 0.82, 95% CI 0.69-0.98, P = 0.026) and at 15q25 (rs2036534, aOR 0.75, 95% CI 0.61-0.93, P = 0.01; rs6495309, aOR 0.81, 95% CI 0.65-1.00, P = 0.052) were significantly associated with lung cancer risk. The magnitude of the effect was similar to that reported in previous studies, and the association was in the same direction. The effect of SNP in the 5p15 region on the risk of lung cancer was significant only for adenocarcinoma. The two SNP in the 15q25 region were significantly associated with lung cancer risk in ever-smokers and in patients with squamous-cell carcinoma. However, there was no association between the SNP at 6p22 and lung cancer risk., Conclusions: The association between SNP in the 5p15 and 15q25 regions and the risk of lung cancer was confirmed in a Korean population., (© 2012 The Authors. Respirology © 2012 Asian Pacific Society of Respirology.)

A fusion gene between echinoderm microtubule-associated protein-like 4 (EML4) and the anaplastic lymphoma kinase (ALK) has been identified in non-small cell lung cancers (NSCLCs). Although a few studies have evaluated EML4-ALK fusion genes in Korean NSCLCs, the prevalence of different EML4-ALK fusion variants has yet to be clearly assessed. Herein, we have examined the profiles of EML4-ALK fusion gene variants in Korean patients of NSCLCs. EML4-ALK fusion genes have been detected in 10 (6.0%) of 167 patients of NSCLCs and in 9 (7.4%) of 121 patients of adenocarcinoma. Of the 10 patients with fusion genes identified, 8 (80%) were E13;A20 (variant 1) and 2 (20%) were E6;A20, with an additional 33-bp sequence derived from intron 6 of EML4 (variant 3b). These results indicate that the profiles of EML4-ALK fusion gene variants in Korean patients of NSCLC may differ from those in other ethnic populations. Herein, we describe for the first time the profiles of EML4-ALK fusion variants of Korean patients with NSCLCs.