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Abstract The role of inhaled corticosteroids (ICS) in chronic obstructive pulmonary disease (COPD) is debated. We investigated whether the administration of ICS could lower the mortality risk in patients with COPD. We utilized the Korean National Health Insurance Service-National Sample Cohort database from 2002 to 2019. We included patients who had claim codes for COPD and inhalation respiratory medicine at least twice a year. A time-dependent Cox regression model was employed to estimate the association between ICS usage and survival. The cumulative dose of ICS was classified into three groups, and the mortality risk was compared among these groups. Of 16,463 included patients, there were 4395 (26.7%) deaths during the mean follow-up period of 5.0 years. The time-dependent Cox regression model demonstrated that ICS users had a significantly lower mortality risk compared to non-users (adjusted hazard ratio, 0.89; 95% CI, 0.83–0.94; p

Background Mechanical power (MP) has been reported to be associated with clinical outcomes. Because the original MP equation is derived from paralyzed patients under volume-controlled ventilation, its application in practice could be limited in patients receiving pressure-controlled ventilation (PCV). Recently, a simplified equation for patients under PCV was developed. We investigated the association between MP and intensive care unit (ICU) mortality. Methods We conducted a retrospective analysis of Korean data from the Fourth International Study of Mechanical Ventilation. We extracted data of patients under PCV on day 1 and calculated MP using the following simplified equation: MPPCV = 0.098 ∙ respiratory rate ∙ tidal volume ∙ (ΔPinsp + positive end-expiratory pressure), where ΔPinsp is the change in airway pressure during inspiration. Patients were divided into survivors and non-survivors and then compared. Multivariable logistic regression was performed to determine association between MPPCV and ICU mortality. The interaction of MPPCV and use of neuromuscular blocking agent (NMBA) was also analyzed. Results A total of 125 patients was eligible for final analysis, of whom 38 died in the ICU. MPPCV was higher in non-survivors (17.6 vs. 26.3 J/min, P

Abstract Background Viral infection is a risk factor for asthma exacerbation (AE). However, bacterial infections related to AE in adults are poorly known. On the other hand, obese patients with asthma have their own clinical and biological characteristics compared with non-obese patients. Methods We investigated the differences in isolated pathogens for AE between obese and non-obese patients with asthma. We included 407 patients with AE from 24 medical centers in Korea. Microorganisms isolated from culture, RT-PCR or serologic tests using lower respiratory tract specimens were retrospectively investigated. Results A total of 171 obese and 236 non-obese patients with asthma were included for analysis. Compared to non-obese patients, obese patients were associated with women (77.2% vs. 63.6%), never smoker (82.5% vs. 73.9%), shorter duration of asthma (7.9 ± 8.4 vs. 10.5 ± 10.1 years), less history of pulmonary tuberculosis (8.8% vs. 17.4%), and more comorbidity of allergic rhinitis (48.5% vs. 0.8%). Viral and/or bacterial infections were detected in 205 patients (50.4%) with AE. The numbers of patients with viral only, bacterial only, or both infections were 119, 49, and 37, respectively. The most commonly isolated bacterium was Streptococcus pneumoniae, followed by Pseudomonas aeruginosa and Chlamydia pneumoniae. Obese patients showed a lower incidence of Chlamydia pneumoniae infection. In the non-obese group, bacterial infection, especially Chlamydia pneumoniae infection, was significantly associated with the duration of systemic corticosteroid use (13.6 ± 19.8 vs. 9.7 ± 6.7 days, p = 0.049). Conclusion Bacterial infection was associated with a longer period of corticosteroid use in the non-obese group. Acute Chlamydia pneumoniae infection was less associated with obese patients with AE. Further well-designed studies are needed to evaluate microorganisms and the efficacy of antibiotics in patients with AE.

Background The Global Initiative for Chronic Obstructive Lung Disease (GOLD) update 2023 proposed new definitions of chronic obstructive pulmonary disease (COPD) and COPD exacerbation. However, an agreement on the definitions has not been made, either internationally or domestically. This study aimed to reach an agreement between experts on the new definitions of COPD and COPD exacerbation in South Korea. Methods A modified Delphi method was used to make an agreement on the definitions of COPD and COPD exacerbation proposed by the GOLD update 2023. We performed two rounds of the survey including 15 Korean experts on COPD, asthma, and tuberculosis. Results More than two-thirds of the experts agreed on 12 of the 13 statements related to the definitions of COPD and COPD exacerbation in the two rounds of the survey. The experts agreed on the definitions of COPD and COPD exacerbation that should be revised in line with the definitions proposed by the GOLD update 2023. However, the experts showed an uncertain opinion on the statement that the definition of COPD includes patients with persistent airflow obstruction due to bronchiectasis. Conclusion Based on this Delphi survey, experts’ agreement was made on the definitions of COPD and COPD exacerbation proposed by the GOLD update 2023.

Purpose To investigate the incidence, outcomes, and imaging characteristics of clustered microcysts detected on breast US in asymptomatic women, and suggest appropriate management guidelines. Materials and Methods We identified and reviewed the lesions recorded as “clustered microcysts” on breast US performed in asymptomatic women between August 2014 and December 2019. The final diagnosis was based on pathology and imaging follow-up results for at least 12 months. Results The incidence was 1.5% and 100 patients with 117 lesions were included. Among 117 lesions, 3 (2.6%), 2 (1.7%), and 112 (95.7%) were malignant, high-risk benign, and benign lesions, respectively. The malignant lesions included two cases of ductal carcinoma in situ and one invasive ductal carcinoma. Two of them were assessed as category 4, showing mammographic suspicious microcalcifications and internal vascularity on Doppler US. The remainder was a false negative case and showed echo pattern change on the 12-month follow-up US. Conclusion The incidence of clustered microcysts on breast US in asymptomatic women was 1.5% and malignancy rate was 2.6% (3 of 117). Knowledge of outcomes and imaging features of benign and malignant clustered microcysts may be helpful for radiologists, thereby aiding categorization and management recommendations.

Chronic obstructive pulmonary disease (COPD) has been regarded as a disease of smokers, but the prevalence of non-smoking COPD patients have been reported to be considerable. We investigated differences in clinical characteristics between smoking and non-smoking COPD patients. We used data from the Korea COPD Subgroup Study (KOCOSS) database, which is a multicenter cohort that recruits patients from 54 medical centres in Korea. Comprehensive comparisons of smoking and non-smoking COPD patients were performed based on general characteristics, exacerbations, symptom scores, radiological findings, and lung-function tests. Of the 2477 patients included in the study, 8.1% were non-smokers and 91.9% were smokers. Non-smoking COPD patients were more likely to be female and to have a higher body mass index and lower level of education. Non-smoking COPD patients had more comorbidities, including hypertension, osteoporosis, and gastroesophageal reflux disease, and experienced more respiratory and allergic diseases. No significant differences in exacerbation rates, symptom scores, or exercise capacity scores were observed between the two groups. Smoking COPD patients had more emphysematous lung according to the radiological findings, and non-smoking patients had more tuberculosis-destroyed lung and bronchiectasis. Lung-function testing revealed no significant difference in the forced expiratory capacity in 1 sec between the two groups, but smokers had more rapid lung-function decline in the 5 years of follow-up data. We found differences in general characteristics and radiological findings between smoking and non-smoking COPD patients. No significant differences in exacerbation or symptom scores were observed, but decline in lung function was less steep in non-smoking patients. Supplemental data for this article is available online at https://doi.org/10.1080/15412555.2022.2053088 .

Abstract Inhaled long-acting muscarinic antagonist (LAMA) is recommended for the treatment of chronic obstructive pulmonary disease (COPD). However, there is still concern that LAMA may cause cardiovascular adverse events in COPD patients. Therefore, this study aimed to determine whether the administration of tiotropium, the first commercially available LAMA, could increase the risk of coronary heart disease (CHD) in COPD patients through a nationwide cohort study. We used the Korean National Health Insurance Service-National Sample Cohort (NHIS-NSC) database between 2002 and 2014 for the analysis. We applied a washout period of COPD diagnosis during 2002–2003 and excluded the patients who used an inhaler before the diagnosis of COPD. We also excluded patients who were diagnosed with CHD before inhaler use. Among a total of 5787 COPD patients, 1074 patients were diagnosed with CHD. In the Cox regression models with time-dependent tiotropium usage, we found that tiotropium significantly increased the risk of CHD in a subgroup of age $$\ge \hspace{0.17em}$$ ≥ 55 years compared to non-users of tiotropium (adjusted hazard ratio [aHR], 1.24; 95% confidence interval [CI], 1.003–1.54). When analyzed by dividing into tertiles (high/middle/low) according to the cumulative tiotropium exposure, the high tertile exposure group of tiotropium was associated with a higher risk of CHD compared with the low tertile exposure group of tiotropium. Additionally, the risk of CHD was higher in the high tertile exposure group of tiotropium in the age 55 and older group and in the never smoker group. When prescribing tiotropium for COPD patients, particularly those over 55 years of age and never-smokers, it is desirable to evaluate the risk of CHD in advance and closely follow-up for CHD occurrence.

Background/Aims There are few studies describing contemporary status of mechanical ventilation in Korea. We investigated changes in management and outcome of mechanical ventilation in Korea. Methods International, prospective observational cohort studies have been conducted every 6 years since 1998. Korean intensive care units (ICUs) participated in 2010 and 2016 cohorts. We compared 2016 and 2010 Korean data. Results Two hundred and twenty-six patients from 18 ICUs and 275 patients from 12 ICUs enrolled in 2016 and 2010, respectively. In 2016 compared to 2010, use of non-invasive ventilation outside ICU increased (10.2% vs. 2.5%, p = 0.001). Pressure-control ventilation was the most common mode in both groups. Initial tidal volume (7.1 mL/kg vs. 7.4 mL/kg, p = 0.372) and positive end-expiratory pressure (6 cmH2O vs. 6 cmH2O, p = 0.141) were similar, but peak pressure (22 cmH2O vs. 24 cmH2O, p = 0.011) was lower in 2016. More patients received sedatives (70.7% vs. 57.0%, p = 0.002) and analgesics (86.5% vs. 51.1%, p < 0.001) in 2016. The awakening (48.4% vs. 31.0%, p = 0.002) was more frequently attempted in 2016. The accidental extubation rate decreased to one tenth of what it was in 2010 (1.1% vs. 10.2%, p < 0.001). The ICU mortality did not change (31.4% vs. 35.6%, p = 0.343) but ICU length of stay showed a decreasing trend (9 days vs. 10 days, p = 0.054) in 2016. Conclusions There were temporal changes in care of patients on mechanical ventilation including better control of pain and agitation, and active attempt of awakening.

BackgroundPatients with chronic obstructive pulmonary disease (COPD) have an increased risk of developing lung cancer. Some studies have also suggested that diabetes mellitus (DM) may increase the risk of developing lung cancer. This study aimed to investigate whether type 2 DM (T2DM) is associated with an increased risk of lung cancer in patients with COPD.Materials and methodsWe conducted a retrospective analysis on two cohorts: the National Health Insurance Service-National Sample Cohort (NHIS-NSC) of Korea and the Common Data Model (CDM) database of a university hospital. Among patients newly diagnosed with COPD in each cohort, those with a lung cancer diagnosis were included, and a control group was selected through propensity score matching. We used the Kaplan–Meier analysis and Cox proportional hazard models to compare lung cancer incidence between patients with COPD and T2DM and those without T2DM.ResultsIn the NHIS-NSC and CDM cohorts, we enrolled 3,474 and 858 patients with COPD, respectively. In both cohorts, T2DM was associated with an increased risk of lung cancer [NHIS-NSC: adjusted hazard ratio (aHR), 1.20; 95% confidence interval (CI), 1.02–1.41; and CDM: aHR, 1.45; 95% CI, 1.02–2.07). Furthermore, in the NHIS-NSC, among patients with COPD and T2DM, the risk of lung cancer was higher in current smokers than in never-smokers (aHR, 1.45; 95% CI, 1.09–1.91); in smokers with ≥30 pack-years than in never-smokers (aHR, 1.82; 95% CI, 1.49–2.25); and in rural residents than in metropolitan residents (aHR, 1.33; 95% CI, 1.06–1.68).ConclusionOur findings suggest that patients with COPD and T2DM may have an increased risk of developing lung cancer compared to those without T2DM.

Background Because the etiologies of bronchiectasis and related diseases vary significantly among different regions and ethnicities, this study aimed to develop a diagnostic bundle for bronchiectasis in South Korea. Methods A modified Delphi method was used to develop expert consensus statements on a diagnostic bundle for bronchiectasis in South Korea. Initial statements proposed by a core panel, based on international bronchiectasis guidelines, were discussed in an online meeting and two email surveys by a panel of experts (≥70% agreement). Results The study involved 21 expert participants, and 30 statements regarding a diagnostic bundle for bronchiectasis were classified as recommended, conditional, or not recommended. The consensus statements of the expert panel were as follows: A standardized diagnostic bundle is useful in clinical practice; diagnostic tests for specific diseases, including immunodeficiency and allergic bronchopulmonary aspergillosis, are necessary when clinically suspected; initial diagnostic tests, including sputum microbiology and spirometry, are essential in all patients with bronchiectasis, and patients suspected with rare causes such as primary ciliary dyskinesia should be referred to specialized centers. Conclusion Based on this Delphi survey, expert consensus statements were generated including specific diagnostic, laboratory, microbiological, and pulmonary function tests required to manage patients with bronchiectasis in South Korea.

Background Although respiratory tract infection is one of the most important factors triggering acute exacerbation of chronic obstructive pulmonary disease (AE-COPD), limited data are available to suggest an epidemiologic pattern of microbiology in South Korea. Methods A multicenter observational study was conducted between January 2015 and December 2018 across 28 hospitals in South Korea. Adult patients with moderate-to-severe acute exacerbations of COPD were eligible to participate in the present study. The participants underwent all conventional tests to identify etiology of microbial pathogenesis. The primary outcome was the percentage of different microbiological pathogens causing AE-COPD. A comparative microbiological analysis of the patients with overlapping asthma–COPD (ACO) and pure COPD was performed. Results We included 1,186 patients with AE-COPD. Patients with pure COPD constituted 87.9% and those with ACO accounted for 12.1%. Nearly half of the patients used an inhaled corticosteroid-containing regimen and one-fifth used systemic corticosteroids. Respiratory pathogens were found in 55.3% of all such patients. Bacteria and viruses were detected in 33% and 33.2%, respectively. Bacterial and viral coinfections were found in 10.9%. The most frequently detected bacteria were Pseudomonas aeruginosa (9.8%), and the most frequently detected virus was influenza A (10.4%). Multiple bacterial infections were more likely to appear in ACO than in pure COPD (8.3% vs. 3.6%, p=0.016). Conclusion Distinct microbiological patterns were identified in patients with moderate-to-severe AE-COPD in South Korea. These findings may improve evidence-based management of patients with AE-COPD and represent the basis for further studies investigating infectious pathogens in patients with COPD.

BackgroundThe clinical implication of bronchodilator response (BDR) is not fully understood. However, BDR is frequently present in patients with chronic obstructive pulmonary disease (COPD). We identified the differences in clinical features regarding BDR. In addition, we divided BDR into BDR for forced expiratory volume in 1 s (FEV1) and BDR for forced vital capacity (FVC; i.e., BDR-FEV1 and BDR-FVC, respectively) and analyzed clinical significance.MethodsWe used data from the Korea COPD Subgroup Study, a multicenter cohort study of COPD patients recruited from 54 centers in South Korea since April 2012. We analyzed differences in baseline characteristics, 1-year exacerbation rate, and 3-year FEV1 decline between BDR negative and positive patients. Moreover, we analyzed the differences in clinical features between BDR-FEV1 positive and negative patients and between BDR-FVC positive and negative patients.ResultsOf the 2,181 patients enrolled in this study, 366 (16.8%) were BDR positive. BDR positive patients were more likely to be ever-smokers and to have a lower body mass index and higher symptom scores compared to BDR negative patients. Baseline FEV1 and FEV1/FVC were lower in the BDR positive compared to the BDR negative group (1.7 ± 0.6 and 1.6 ± 0.5, respectively, p < 0.01; 50.9 ± 12.1 and 46.5 ± 14.8, respectively, p < 0.01). BDR positive patients were more likely to have been diagnosed with asthma-COPD overlap and to receive inhaled corticosteroids (ICS) than BDR negative patients. BDR-FVC patients were more likely to be smokers, suffer from worse symptoms and have lower lung function than those with no BDR-FVC. BDR had no significant effect on 1-year moderate to severe or severe exacerbation rates or 3-year annual FEV1 decline. Interactive effects of ICS and BDR on the exacerbation rate were not significant in any group.ConclusionsIn this study, BDR positive patients were more likely to be ever-smokers and to have worse symptoms and lung function than BDR negative patients. BDR-FVC was associated with worse symptom control and lung function compared to BDR-FEV1. However, there were no significant differences in exacerbation rate or decline in lung function in any BDR group. In addition, the effects of ICS on exacerbations were not significant in any group.

Abstract Conventional deep learning (DL) algorithm requires full supervision of annotating the region of interest (ROI) that is laborious and often biased. We aimed to develop a weakly-supervised DL algorithm that diagnosis breast cancer at ultrasound without image annotation. Weakly-supervised DL algorithms were implemented with three networks (VGG16, ResNet34, and GoogLeNet) and trained using 1000 unannotated US images (500 benign and 500 malignant masses). Two sets of 200 images (100 benign and 100 malignant masses) were used for internal and external validation sets. For comparison with fully-supervised algorithms, ROI annotation was performed manually and automatically. Diagnostic performances were calculated as the area under the receiver operating characteristic curve (AUC). Using the class activation map, we determined how accurately the weakly-supervised DL algorithms localized the breast masses. For internal validation sets, the weakly-supervised DL algorithms achieved excellent diagnostic performances, with AUC values of 0.92–0.96, which were not statistically different (all Ps > 0.05) from those of fully-supervised DL algorithms with either manual or automated ROI annotation (AUC, 0.92–0.96). For external validation sets, the weakly-supervised DL algorithms achieved AUC values of 0.86–0.90, which were not statistically different (Ps > 0.05) or higher (P = 0.04, VGG16 with automated ROI annotation) from those of fully-supervised DL algorithms (AUC, 0.84–0.92). In internal and external validation sets, weakly-supervised algorithms could localize 100% of malignant masses, except for ResNet34 (98%). The weakly-supervised DL algorithms developed in the present study were feasible for US diagnosis of breast cancer with well-performing localization and differential diagnosis.

Abstract Emphysema is an important feature of chronic obstructive pulmonary disease (COPD). Genetic factors likely affect emphysema pathogenesis, but this question has predominantly been studied in those of European ancestry. In this study, we sought to determine genetic components of emphysema severity and characterize the potential function of the associated loci in Korean population. We performed a genome-wide association study (GWAS) on quantitative emphysema in subjects with or without COPD from two Korean COPD cohorts. We investigated the functional consequences of the loci using epigenetic annotation and gene expression data. We also compared our GWAS results with an epigenome-wide association study and previous differential gene expression analysis. In total, 548 subjects (476 [86.9%] male) including 514 COPD patients were evaluated. We identified one genome-wide significant SNP (P

Abstract This research identified the different ways in which K-beauty social media influencers (SMIs) impact consumers’ tendencies to accept new products by closely investigating their sponsorship displays and product exposure methods. We conducted an experiment to examine how influencers’ posts affect Chinese millennial consumers’ acceptance of new products. We used a 2 (influencer type: celebrity versus general public) × 2 (sponsorship display status: display versus no display) × 2 (product exposure method: exposure versus no exposure) factorial design. The findings reveal that the social media posts that made consumers most likely to accept a new product were created by a general public influencer and did not include a display of any sponsorship affiliation with the product. Additionally, there was a significant interplay between the influencer type, sponsorship display status, and product exposure method regarding consumers’ acceptance intention toward a new product. A consumer was most likely to accept and purchase a new product when three factors (general public influencer, sponsorship displayed, and product exposed) were combined. Based on the findings, we draw important implications and present marketing strategies for companies in the beauty industry that use SMI marketing.

Abstract Background Epidermal growth factor receptor (EGFR) mutations in non–small-cell lung cancer predict sensitivity to EGFR tyrosine kinase inhibitors (TKIs). EGFR mutation types are associated with efficacy of EGFR TKIs. We investigated the clinical outcomes of afatinib, erlotinib, and gefitinib according to EGFR mutation type in patients with lung adenocarcinoma. Methods Between May 2010 and December 2018, we investigated 363 patients with advanced lung adenocarcinoma harboring EGFR mutations who received EGFR TKIs. Efficacies of EGFR TKIs such as response rate, progression-free survival (PFS), and overall survival (OS) were retrospectively evaluated according to exon 19 deletion (E19del), L858R point mutation (L858R) and uncommon mutations. Results The frequency of E19del was 48.2%, that of L858R was 42.4%, and that of uncommon mutations was 9.4%. E19del and L858R were associated with superior PFS and OS compared with uncommon mutations. Erlotinib showed significantly inferior OS than other TKIs (30.8 ± 3.3 in erlotinib vs. 39.1 ± 4.3 in afatinib vs. 48.4 ± 6.3 in gefitinib; p = 0.031) in patients with L858R. Gefitinib showed significantly inferior PFS (4.6 ± 1.1 in gefitinib vs. 11.6 ± 2.7 in afatinib vs. 10.6 ± 2.7 in erlotinib; p = 0.049) in patients with uncommon mutations. Conclusion Afatinib was significantly associated with a longer PFS, presenting constant effectiveness in all EGFR mutation types. Caution may be needed on the use of erlotinib for L858R and the use of gefitinib for uncommon EGFR mutations.

Abstract The recent advancements in information and communication technologies have altered instructional contexts and re-shaped them into smart learning environments. One of the most common practices of these environments are learning management systems (LMS) where the learners and instructors utilize a software platform to fulfill, support and manage instructional activities around predefined objectives. Successful implementations of LMS have brought a variety on its usage from different cultures, genders, age groups or schooling levels. Hence, this study focuses on understanding the role of culture on LMS design, in along with the effects of gender, age and school year variables. The study participants were German (n = 83) and Spanish (n = 83) university students attending a fully online course offered by a South Korean university. At the end of the course, the students were asked to fulfill a survey on effective LMS design by pointing which features of LMS were more important for them. The survey included twenty questions on four major design factors; content management (six items), ease of use (five items), communication within LMS (four item) and screen design (five items). The dataset was analyzed by non-parametric statistical techniques around four variables on four dimensions (and their related survey questions). The most important result was insufficiency of one unique LMS design for all students which demonstrates the necessity of student demographics tailored smart systems. Additionally, age and gender variables were not making significant differences on LMS design as much as culture and school year variables. The study also revealed that while German students would appreciate goal-oriented individual learning, Spanish students would value process-oriented group learning with active communication. Furthermore, many features of LMS were highly valued by the freshman students more than other levels. The paper discusses these variables with possible explanations from the literature and depicts implementations for future design practices.

Background/Aims Many chronic obstructive pulmonary disease (COPD) patients have physical limitations. We investigated EuroQol five-dimensions five-level (EQ-5D-5L) of COPD patients to assess quality of life, and assessed indirect burden including time expenditure to visit doctor, home care rate, and caregiver related burden. Methods We recruited 355 COPD patients according to severity of airflow limitation that severity was set at 10% mild, 40% moderate, 30% severe, and 20% very severe in two primary and 11 secondary/tertiary hospitals. Eligible patients were aged ≥ 40 years, who have been diagnosed with COPD for more than 1 year. Patients were recruited between June 2015 and October 2016. Results The quality of life tended to decline with age, from mild to very severe impairment, as revealed by the EQ-5D-5L scores and the EQ visual analog scale. Family caregivers accompanied 22.6% of patients who visited outpatient clinics, and 25% of stage IV COPD patients. During emergency visits and hospitalization, this figure increased to > 60%. The home care rates were 28.5% for stage I patients, and 34.4, 31.8, and 52% for stage II to IV patients, respectively. The percentage of caregivers who stopped working was 13.6%. The EQ-5D index was strongly associated with the dyspnea scale (r = –0.64, p < 0.001). The average required time to see a doctor and visit the pharmacy was 154 minutes. Conclusions In patients with COPD, the EQ-5D index decreased and disease-related home caregiving increased with airflow limitation. We considered the caregiver- related burden when making a strategy for COPD management.

Abstract Background Radial endobronchial ultrasound (R‐EBUS) transbronchial lung biopsy (TBLB) improves the diagnostic yield from peripheral pulmonary lesions (PPLs). However, the small specimens obtained using small forceps through a guide sheath (GS) may impede diagnosis and molecular analysis. Here, we investigated the diagnostic significance of additional conventional TBLB with standard forceps after R‐EBUS‐GS‐guided TBLB. Methods We retrospectively reviewed data from 55 patients who underwent conventional TBLB after R‐EBUS‐GS‐guided TBLB for PPL diagnosis. Procedures were performed on single PPLs with no visible lesions on bronchoscopy. In cases with inconclusive pathologic confirmation, final diagnoses were made based on pathologic specimens or clinical observations. Results The median size of the target lesions was 28 mm. The appearances on computed tomography images were solid (n = 45, 81.8%), part‐solid (n = 7, 12.7%), and cavitary nodules (n = 3, 5.5%). A computed tomography bronchus sign was present in 35 (63.6%) cases, and a radial probe was positioned within target lesion in 32 (58.2%) cases. R‐EBUS‐GS‐guided TBLB was diagnostic in 30 (54.5%) patients, and subsequent conventional TBLB yielded additional diagnostic information in 8 (14.5%) patients. Probe positioning within target lesions and the outer margin of PPLs more than 1 cm from pleura were significantly associated with enhanced diagnostic yield from the combined procedures. In conventional TBLB, probe positioning within target lesions (75.0% vs. 11.8%, P = 0.004) and characteristic of nonsolid nodules (83.3% vs. 15.8%, P = 0.006) were significantly associated with additional diagnostic utility. Conclusions Conventional TBLB following R‐EBUS‐GS‐guided TBLB could be a useful procedure for diagnosing PPLs, especially for nonsolid nodules. Key points Significant findings of the study: Additional conventional TBLB with standard forceps after R‐EBUS‐GS‐guided TBLB yielded an additional 14.5% diagnostic utility for peripheral pulmonary lesions. For conventional TBLB, probe positioning within target lesions and nonsolid nodules were significantly associated with additional diagnostic utility. What this study adds: Conventional TBLB with standard forceps after R‐EBUS‐GS‐guided TBLB is an effective and economically accessible diagnostic tool for peripheral pulmonary lesions.

Abstract Background Spontaneous remission (SR) of cancer is a very rare phenomenon of unknown mechanism. In particular, SR of non-small cell lung cancer (NSCLC) has been scarcely reported. We present the case of a 74-year-old woman with advanced, poorly differentiated NSCLC (highly expressing programmed death ligand-1 [PD-L1]) that progressed despite multiple lines of chemotherapy but then spontaneously remitted. CASE presentation The patient presented with hemoptysis and was diagnosed with stage IIIA poorly differentiated NSCLC via bronchoscopic biopsy. She had an unremarkable medical history and moderate performance status. The initial treatment plan was surgery after neoadjuvant chemotherapy. Despite conventional chemotherapy, follow-up chest computed tomography (CT) showed gradual tumor progression and she decided against further treatment after fifth-line chemotherapy. However, the size of lung mass was markedly decreased on follow-up chest CT one year after ceasing chemotherapy. Also, follow-up positron emission tomography images showed decreased metabolic activity in the lung mass and a percutaneous biopsy specimen from the diminished lung mass revealed no viable tumor cells. A diagnosis of SR of NSCLC was confirmed, and the patient was without tumor progression on follow-up nine months later. Later, PD-L1 immunostaining revealed high positivity (> 99%) in initial tumor cells. Conclusion Our case showing SR of poorly advanced NSCLC refractory to multiple lines of chemotherapy suggested the association between immunity and tumor regression.

Background The detection rate of ground‐glass nodules (GGNs) in the lung has increased with the increased use of low‐dose computed tomography (CT) of the chest for cancer screening; however, limited data is available on the natural history, follow‐up, and treatment of GGNs. The aim of this study was to identify factors associated with an increase in the size of GGNs. Methods A total of 338 patients (mean ages, 59.8 years; males, 35.5%) with 689 nodules who underwent chest CT at our institute between June 2004 and February 2014 were included in this study. The cut‐off date of follow‐up was August 2018. We analyzed the size, solidity, number, and margins of the nodules compared with their appearance on previous chest CT images. The Cox proportional hazard model was used to identify risk factors associated with nodule growth. Results The median follow‐up period was 21.8 months. Of the 338 patients, 38.5% had a history of malignancy, including lung cancer (8.9%). Among the 689 nodules, the median size of the lesions was 6.0 mm (IQR, 5–8 mm), and the proportion of nodules with size ≥10 mm and multiplicity was 17.1% and 66.3%, respectively. Compared to the nodules without an increase in size, the 79 nodules with an increase in size during the follow‐up period were initially larger (growth group, 7.0 mm vs. non‐growth group, 6.0 mm; P = 0.027), more likely to have a size ≥10 mm (26.6% vs. 15.9%; P = 0.018), and had less frequent multiplicity (54.4% vs. 67.9%, P = 0.028). In the multivariate analysis, nodule size ≥10 mm (hazard ratio [HR], 2.044; P = 0.005), a patient history of lung cancer (HR: 2.190, P = 0.006), and solitary nodule (HR: 2.499, P < 0.001) were independent risk factors for nodule growth. Conclusion Careful follow‐up of GGNs is warranted in patients with a history of malignancy, a large , or a solitary nodule.

Abstract Background Although infections caused by nontuberculous mycobacteria (NTM) are increasing in prevalence, there are few data about hemoptysis in patients with NTM lung disease. This study investigated the characteristics and prognosis of hemoptysis secondary to NTM infection. Methods Following a retrospective review of cases managed between 2006 and 2016, 183 patients with NTM lung disease were enrolled and analyzed. Results Among 183 patients with NTM lung disease, Mycobacterium intracellulare (n = 64, 35%) was the major cause of NTM infection, followed by M. avium (n = 59, 32.2%) and M. abscessus complex (n = 40, 21.9%). Hemoptysis developed in 78 patients (42.6%), among whom 33 (42.3%) required bronchial artery embolization (BAE). Between patients with and without hemoptysis, there were no significant differences with respect to sex, radiographic manifestations, distribution over 3 lobes on chest computed tomography, history of pulmonary tuberculosis, antiplatelet or anticoagulation therapy, and species of NTM. However, mean age at diagnosis was significantly lower in the hemoptysis group in univariate and multivariate analyses (65.7 ± 12.8 vs. 59.7 ± 11.8, P = 0.002, odds ratio: 0.969, 95% confidence interval: 0.944–0.996). Among patients with hemoptysis, those requiring medical therapy and those requiring BAE were not significantly different in terms of demographic characteristics, radiographic manifestations, and distribution over 3 lobes. All patients who received BAE showed immediate clinical improvement, no procedure-related complications, and none of them died during the period under review. Conclusions NTM lung disease patients commonly experienced hemoptysis without specific risk factors except for relatively young age. Although some patients with hemoptysis needed BAE, the success rate of BAE was high, and there were no serious complications associated with BAE.

A distinct calcification pattern is one of the criteria for determining the malignancy of breast cancer according to the Breast Imaging Reporting and Data System. A mass almost entirely replaced by calcification, however, is difficult to categorize and likely to be misdiagnosed. We present the report of two patients with invasive carcinoma of the breast that presented as a mass replaced by calcification on mammography. In the first case, the mass was confirmed as a mixed carcinoma comprising mucinous and micropapillary carcinoma, and in the second case, the mass was a mucinous carcinoma. Diagnosis of cancer in the latter case was missed as the mass had been assessed as a category 2 typically benign calcification at the first screening mammography 2 years ago. This report merits publication because it shows that a mass replaced by calcification on mammography can be misdiagnosed as a benign finding.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrosing interstitial pneumonia, which presents with a progressive worsening dyspnea, and thus a poor outcome. The members of the Korean Academy of Tuberculosis and Respiratory Diseases as well as the participating members of the Korea Interstitial Lung Disease Study Group drafted this clinical practice guideline for IPF management. This guideline includes a wide range of topics, including the epidemiology, pathogenesis, risk factors, clinical features, diagnosis, treatment, prognosis, and acute exacerbation of IPF in Korea. Additionally, we suggested the PICO for the use of pirfenidone and nintendanib and for lung transplantation for the treatment of patients with IPF through a systemic literature review using experts' help in conducting a meta-analysis. We recommend this guideline to physicians, other health care professionals, and government personnel in Korea, to facilitate the treatment of patients with IPF.

Purpose The purpose of this study was to record and evaluate interobserver agreement as quality control for the modified categorization of screening breast ultrasound developed by the Alliance for Breast Cancer Screening in Korea (ABCS-K) for the Mammography and Ultrasonography Study for Breast Cancer Screening Effectiveness (MUST-BE) trial. Methods Eight breast radiologists with 4-16 years of experience participated in 2 rounds of quality control testing for the MUST-BE trial. Two investigators randomly selected 125 and 100 cases of breast lesions with different ratios of malignant and benign lesions. Two versions of the modified categorization were tested. The initially modified classification was developed after the first quality control workshop, and the re-modified classification was developed after the second workshop. The re-modified categorization established by ABCS-K added size criteria and the anterior-posterior ratio compared with the initially modified classification. After a brief lecture on the modified categorization system prior to each quality control test, the eight radiologists independently categorized the lesions using the modified categorization. Interobserver agreement was measured using kappa statistics. Results The overall kappa values for the modified categorizations indicated moderate to substantial degrees of agreement (initially modified categorization and re-modified categorization: κ=0.52 and κ=0.63, respectively). The kappa values for the subcategories of category 4 were 0.37 (95% confidence interval [CI], 0.24 to 0.52) and 0.39 (95% CI, 0.31 to 0.49), respectively. The overall kappa values for both the initially modified categorization and the re-modified categorization indicated a substantial degree of agreement when dichotomizing the interpretation as benign or suspicious. Conclusion The preliminary results demonstrated acceptable interobserver agreement for the modified categorization.

Background Understanding the burden of disease is important to establish cost-effective treatment strategies and to allocate healthcare resources appropriately. However, little reliable information is available regarding the overall economic burden imposed by chronic obstructive pulmonary disease (COPD) in Korea. Methods This study is a multicenter observational research on the COPD burden in Korea. Total COPD costs were comprised of three categories: direct medical, direct non-medical, and indirect costs. For direct medical costs, institutional investigation was performed at 13 medical facilities mainly based on the claims data. For direct non-medical and indirect costs, site-based surveys were administered to the COPD patients during routine visits. Total costs were estimated using the COPD population defined in the recent report. Results The estimated total costs were approximately 1,245 million US dollar (1,408 billion Korean won). Direct medical costs comprised approximately 20% of the total estimated costs. Of these, formal medical costs held more than 80%. As direct non-medical costs, nursing costs made up the largest percentage (39%) of the total estimated costs. Costs for COPD-related loss of productivity formed four fifths of indirect costs, and accounted for up to 33% of the total costs. Conclusion This study shows for the first time the direct and indirect costs of COPD in Korea. The total costs were enormous, and the costs of nursing and lost productivity comprised approximately 70% of total costs. The results provide insight for an effective allocation of healthcare resources and to inform establishment of strategies to reduce national burden of COPD.

In this letter, we present high-performance AlGaN/GaN high electron mobility transistor (HEMT) by 3-dimensional (3D) tri-gate. Due to the excellent channel control of tri-gate structure, the tri-gate HEMT shows the low subthreshold swing (SS) of 65 mV/decade, low off-state drain leakage current (Ioff) of 7 nA/mm, and On/Off ratio up to 7.6 × 107. Furthermore, we combined the tri-gate structure and metal oxide semiconductor (MOS) structure. The tri-gate MOS-HEMT with high-k dielectric oxide HfO2 was fabricated. The good interface between HfO2 and AlGaN and strain-induce polarization increase the carrier concentration. Compared to the tri-gate HEMT, the increased maximum drain current, higher On/Off ratio and better breakdown voltage is demonstrated by implanted the high k dielectric HfO2. The improved electrical performance of tri-gate MOS-HEMT shows potential for next generation power application.

Adenocarcinoma is the most common type of non-small cell lung cancer. Some causative genomic alterations in epidermal growth factor receptor (EGFR), including deletions in exon 19 (E19 dels) and a point mutation in E21, are known to have favourable prognoses due to sensitivity to tyrosine kinase inhibitors; however, the prognoses of other uncommon mutations are unclear. This study analysed the clinical significance of EGFR mutation types in lung adenocarcinoma. We retrospectively reviewed 1,020 subjects (mean age: 66.8 years, female: 41.7%) who were diagnosed with advanced lung adenocarcinoma, had EGFR mutation data, and did not undergo surgery from five medical institutes between 2010 and 2016. Subjects were classified according to EGFR mutation status, particularly for exon-specific mutations. EGFR positivity was defined as the presence of mutation and EGFR negativity was defined as wild-type EGFR. EGFR positivity was 38.0%, with the incidence of mutations in E18, E19, E20, and E21 was 3.6%, 51.0%, 3.4%, and 42.0%, respectively. The EGFR positive group survived significantly longer than the negative group (p

Abstract Background There has been a steady increase in the aging population and an increase in the need for long-term care beds in institutions and hospitals (LTCHs) in Korea. The aim of this study was to investigate prognosis and to identify factors contributing to mortality of critically ill patients with respiratory problems who were directly transferred to intensive care units (ICU) from LTCHs. Methods Following a retrospective review of clinical data and radiographic findings between July 2009 and September 2016, we included 111 patients with respiratory problems who had visited the emergency room (ER) transferred from LTCHs due to respiratory symptoms and who were then admitted to the ICU. Results The mean age of the 111 patients was 79 years, and 71 patients (64%) were male. Pneumonia developed in 98 patients (88.3%), pulmonary thromboembolism in 4 (3.6%) and pulmonary tuberculosis in 3 (2.7%). Overall mortality was 19.8% (22/111). Multiple-drug-resistant (MDR) pathogens (odds ratio [OR], 17.43; 95% confidence interval [CI], 1.96–155.40) and serum albumin levels

Chronic obstructive pulmonary disease (COPD) results in high morbidity and mortality among patients nationally and globally. The Korean clinical practice guideline for COPD was revised in 2018. The guideline was drafted by the members of the Korean Academy of Tuberculosis and Respiratory Diseases as well as the participating members of the Health Insurance Review and Assessment Service, Korean Physicians' Association, and Korea Respiration Trouble Association. The revised guideline encompasses a wide range of topics, including the epidemiology, diagnosis, assessment, monitoring, management, exacerbation, and comorbidities of COPD in Korea. We performed systematic reviews assisted by an expert in meta-analysis to draft a guideline on COPD management. We expect this guideline to facilitate the treatment of patients with respiratory conditions by physicians as well other health care professionals and government personnel in South Korea.

Background The objective of this study was to investigate the characteristics and clinical outcomes of critically ill cancer patients admitted to intensive care units (ICUs) in Korea. Methods This was a retrospective cohort study that analyzed prospective collected data from the Validation of Simplified Acute Physiology Score 3 (SAPS3) in Korean ICU (VSKI) study, which is a nationwide, multicenter, and prospective study that considered 5,063 patients from 22 ICUs in Korea over a period of 7 months. Among them, patients older than 18 years of age who were diagnosed with solid or hematologic malignancies prior to admission to the ICU were included in the present study. Results During the study period, a total of 1,762 cancer patients were admitted to the ICUs and 833 of them were deemed eligible for analysis. Six hundred fifty-eight (79%) had solid tumors and 175 (21%) had hematologic malignancies, respectively. Respiratory problems (30.1%) was the most common reason leading to ICU admission. Patients with hematologic malignancies had higher Sequential Organ Failure Assessment (12 vs. 8, P

Abstract Background The effects of corticosteroid-based therapy in patients with idiopathic nonspecific interstitial pneumonia (iNSIP), and factors affecting treatment outcome, are not fully understood. We aimed to investigate the long-term treatment response and factors affecting the treatment outcome in iNSIP patients from a multi-center study in Korea. Methods The Korean interstitial lung disease (ILD) Study Group surveyed ILD patients from 2003 to 2007. Patients were divided into two groups to compare the treatment response: response group (forced vital capacity (FVC) improves ≥10% after 1 year) and non-response group (FVC

Purpose To evaluate an educational effect of the mammography boot camp (MBC) for radiology residents and analyze affecting factors. Materials and Methods Between December 2014 and February 2015, radiology residents in 16 institutions performed the MBC program. We compared the educational effect (score difference between pre- and post-camp test) using 25 case series and analyzed the affecting factors including institution, grades of residents, training periods, presence of sub-specialized breast staff, breast density, and types of cases. Results The mean scores of 92 residents were 52.80 ± 18.10 and 72.50 ± 12.91 in the pre- and post-camp test, respectively (p = 0.001). There was no significant difference of educational effect according to institution (19.70 ± 16.31), grade, or training period. Although the educational effect of non-trainees was superior to that of trainees (28.10 ± 17.55 vs. 15.90 ± 14.22; p = 0.001), the scores of trainees were higher than those of non-trainees. The diagnostic accuracy showed more improvement in a fatty breast and cases with microcalcifications than compared with others. Conclusion The MBC showed an effective educational result for radiology residents when interpretating a mammography. It was helpful even for non-trainees. The institution, grades training period, and presence of sub-specialized breast staff did not affect the educational effect.

Background: We evaluated the feasibility of the reduced field-of-view (rFOV) diffusion-weighted imaging (DWI) with computed DWI technique by comparison and analysis of the inter-method agreement among acquired rFOV DWI (rFOVA), rFOV DWI with computed DWI technique (rFOVS), and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in patients with breast cancer. Methods: A total of 130 patients with biopsy-proven breast cancers who underwent breast MRI from April 2017 to December 2017 were included in this study. The rFOVS were reformatted by calculation of the apparent diffusion coefficient curve obtained from rFOVA b = 0 s/mm2 and b = 500 s/mm2. Visual assessment of the image quality of rFOVA b = 1000 s/mm2, rFOVS, and DCE MRI was performed using a four-point grading system. Morphologic analyses of the index cancer was performed on rFOVA, rFOVS, and DCE MRI. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and contrast of tumor-to-parenchyma (TPC) were calculated. Results: Image quality scores with rFOVA, rFOVS, and DCE MRI were not significantly different (p = 0.357). Lesion analysis of shape, margin, and size of the index cancer also did not show significant differences among the three sequences (p = 0.858, p = 0.242, and p = 0.858, respectively). SNR, CNR, and TPC of DCE MRI were significantly higher than those of rFOVA and rFOVS (p < 0.001, p = 0.001, and p = 0.016, respectively). Significant differences were not found between the SNR, CNR, and TPC of rFOVA and those of rFOVS (p > 0.999, p > 0.999, and p > 0.999, respectively). Conclusion: The rFOVA and rFOVS showed nearly equivalent levels of image quality required for morphological analysis of the tumors and for lesion conspicuity compared with DCE MRI.

Advances in bronchoscopy and CT-guided lung biopsy have improved the evaluation of small pulmonary lesions (PLs), leading to an increase in preoperative histological diagnosis. We aimed to evaluate the efficacy and safety of transbronchial lung biopsy using radial endobronchial ultrasound and virtual bronchoscopic navigation (TBLB-rEBUS&VBN) and CT-guided transthoracic needle biopsy (CT-TNB) for tissue diagnosis of small PLs.A systematic search was performed in five electronic databases, including MEDLINE, EMBASE, Cochrane Library Central Register of Controlled Trials, Web of Science, and Scopus, for relevant studies in May 2016; the selected articles were assessed using meta-analysis. The articles were limited to those published after 2000 that studied small PLs ≤ 3 cm in diameter.From 7345 records, 9 articles on the bronchoscopic (BR) approach and 15 articles on the percutaneous (PC) approach were selected. The pooled diagnostic yield was 75% (95% confidence interval [CI], 69-80) using the BR approach and 93% (95% CI, 90-96) using the PC approach. For PLs ≤ 2 cm, the PC approach (pooled diagnostic yield: 92%, 95% CI: 88-95) was superior to the BR approach (66%, 95% CI: 55-76). However, for PLs > 2 cm but ≤ 3 cm, the diagnostic yield using the BR approach was improved to 81% (95% CI, 75-85). Complications of pneumothorax and hemorrhage were rare with the BR approach but common with the PC approach.CT-TNB was superior to TBLB-rEBUS&VBN for the evaluation of small PLs. However, for lesions greater than 2 cm, the BR approach may be considered considering its diagnostic yield of over 80% and the low risk of procedure-related complications.

OBJECTIVES: The eradication of Helicobacter (H.) pylori allows peptic ulcers in patients infected with the bacteria to be cured. Treatment with the classic triple regimen (proton pump inhibitor, amoxicillin and clarithromycin) has shown decreased efficacy due to increased bacterial resistance to clarithromycin. In our country, the eradication rate by intention to treat with this regimen is 83%. In Brazil, a commercially available regimen for bacterial eradication that uses levofloxacin and amoxicillin with lansoprazole is available; however, its efficacy is not known. Considering that such a treatment may be an alternative to the classic regimen, we aimed to verify its efficacy in H. pylori eradication. METHODS: Patients with peptic ulcer disease infected with H. pylori who had not received prior treatment were treated with the following regimen: 30 mg lansoprazole bid, 1,000 mg amoxicillin bid and 500 mg levofloxacin, once a day for 7 days. RESULTS: A total of 66 patients were evaluated. The patients’ mean age was 52 years, and women comprised 55% of the sample. Duodenal ulcers were present in 50% of cases, and gastric ulcers were present in 30%. The eradication rate was 74% per protocol and 73% by intention to treat. Adverse effects were reported by 49 patients (74%) and were mild to moderate, with a prevalence of diarrhea complaints. CONCLUSIONS: Triple therapy comprising lansoprazole, amoxicillin and levofloxacin for 7 days for the eradication of H. pylori in Brazilian peptic ulcer patients showed a lower efficacy than that of the classic triple regimen.

The use of low-molecular-weight heparin (LMWH) can lead to major life threatening complications, including hematomas. Abdominal wall muscle hematomas are rarely fatal, and encompass a wide spectrum of severity depending on size, etiology, and associated complications; but because of their rarity may be misdiagnosed clinically. We report a fatal case of an 80-year-old female who received LMWH after an episode of pulmonary thromboembolism and was subsequently diagnosed with a large right abdominal wall hematoma complicated with hypovolemic shock and acute kidney injury.

BACKGROUND: The level of body mass index (BMI) that is associated with the lowest mortality in critically ill patients in Asian populations is uncertain. We aimed to examine the association of BMI with hospital mortality in critically ill patients in Korea. METHODS: We conducted a prospective multicenter cohort study of 3,655 critically ill patients in 22 intensive care units (ICUs) in Korea. BMI was categorized into five groups:

Background: Postoperative admission to the surgical intensive care unit (S-ICU) is commonly planned to prevent and treat complications, unnecessary admission to the S-ICU increases medical costs and length of hospital stay. This study aimed evaluated outcome and the predictive factors for mortality in patients admitted to the S-ICU after abdominal surgery. Methods: The 168 patients admitted to the S-ICU immediately after abdominal surgery were reviewed retrospectively from January to December 2011. Results: The mortality rate of patients admitted to the S-ICU after abdominal surgery was 8.9% (15 of 168). Two preoperative factors (body mass index [BMI] < 18.5 kg/m2 [p < 0.001] and serum albumin < 3.0 g/dL [p = 0.018]), two operative factors (the need for transfusion [p = 0.008] or vasopressors [p = 0.013] during surgery), and three postoperative variables (mechanical ventilation immediately following surgery [p < 0.001], sequential organ failure assessment [p = 0.001] and SAPS II [p = 0.001] score) were associated with mortality in univariate analysis. After adjusting for age, gender, and SAPS II by a Cox regression, which revealed that BMI < 18.5 kg/m2 (p < 0.001, hazard ratio [HR] 9.690, 95% confidence interval [CI] 2.990-25.258) and the use of mechanical ventilation on admission to S-ICU (p < 0.001, HR 34.671, 95% CI 6.440-186.649) were independent prognostic factors. Conclusions: In patients in S-ICU after abdominal surgery, low BMI and postsurgical mechanical ventilation should be considered important predictors of mortality.