Application of the Lancet Commission COPD classification to COPD Cohort Population in South Korea.

The Lancet Commissions on COPD recommended a new classification based on five main risk factors. Patients with COPD were prospectively enrolled in a Korean COPD subgroup study cohort between April 2012 and June 2022. Patients were classified according to the etiologies (Type 1: Genetically determined (COPD-G), Type 2: Abnormal lung development (COPD-D), Type 3: Infections (COPD-I), Type 4: Cigarette smoking (COPD-C), Type 5: Biomass and pollution (COPD-P)). The database enrolled 3476 patients. Among 3392 patients, 52 (2 %), 1339 (39 %), 2930 (86 %), and 2221 (65 %) were compatible with type 2 (COPD-D), 3 (COPD-I), 4 (COPD-C), and 5 (COPD-P), respectively. Most patients (71 %, 2405) had multiple risk factors contributing to their COPD. However, 93, 712, and 182 patients had only type 3 (COPD-I), 4 (COPD-C), and 5 (COPD-P), respectively. Type 3 (COPD-I) only patients were significantly younger, more often female, and had lower lung function. Both the rate and frequency of severe exacerbations were significantly higher in type 3 (COPD-I) only patients (p = 0.038 and p = 0.048, respectively). Compared with type 5 (COPD-P) only, type 3 (COPD-I) only was significantly associated with the risk of severe exacerbation (Odds ratio, 5.7 [95 % CI, 1.0-32.4]; P = 0.049, incident rate ratio, 8.7 [95 % CI, 1.7-44.0]; P = 0.009). Many patients were affected by multiple factors. Therefore, it is important to consider not only smoking history, but also other potential risk factors when evaluating patients with COPD. Further research is needed to explore the implications of this new COPD classification system for clinical practice and treatment strategies.

Pulmonary Rehabilitation Is Associated With Decreased Exacerbation and Mortality in Patients With COPD: A Nationwide Korean Study.

BACKGROUND: Poor uptake to pulmonary rehabilitation (PR) is still challenging around the world. There have been few nationwide studies investigating whether PR impacts patient outcomes in COPD. We investigated the change of annual PR implementation rate, medical costs, and COPD outcomes including exacerbation rates and mortality between 2015 and 2019. RESEARCH QUESTION: Does PR implementation improve outcomes in patients with COPD in terms of direct cost, exacerbation, and mortality? STUDY DESIGN AND METHODS: Data of patients with COPD extracted from a large Korean Health Insurance Review and Assessment service database (2015-2019) were analyzed to determine the trends of annual PR implementation rate and direct medical costs of PR. Comparison of COPD exacerbation rates between pre-PR and post-PR, and the time to first exacerbation and mortality rate according to PR implementation, were also assessed. RESULTS: Among all patients with COPD in South Korea, only 1.43% received PR. However, the annual PR implementation rate gradually increased from 0.03% to 1.4% during 4 years, especially after health insurance coverage commencement. The direct medical cost was significantly higher in the PR group than the non-PR group, but the costs in these groups showed decreasing and increasing trends, respectively. Both the incidence rate and frequency of moderate-to-severe and severe exacerbations were lower during the post-PR period compared with the pre-PR period. The time to the first moderate-to-severe and severe exacerbations was longer in the PR group than the non-PR group. Finally, PR implementation was associated with a significant decrease in mortality. INTERPRETATION: We concluded that health insurance coverage increases PR implementation rates. Moreover, PR contributes toward improving outcomes including reducing exacerbation and mortality in patients with COPD. However, despite the well-established benefits of PR, its implementation rate remains suboptimal.

Association Between Air Pollution and Viral Infection in Severe Acute Exacerbation of Chronic Obstructive Pulmonary Disease.

BACKGROUND: Respiratory pathogen infections and air pollution are main causes of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Air pollution has a direct effect on the airway epithelial barrier and the immune system, which can have an influence on infection. However, studies on the relationship between respiratory infections and air pollutants in severe AECOPD are limited. Thus, the objective of this study was to investigate the correlation between air pollution and respiratory pathogen in severe AECOPD. METHODS: This multicenter observational study was conducted by reviewing electronic medical records of patients with AECOPD at 28 hospitals in South Korea. Patients were divided into four groups according to the comprehensive air-quality index (CAI) used in Korea. Identification rates of bacteria and viruses of each group were analyzed. RESULTS: Viral pathogens were identified in 270 (36.7%) of 735 patients. Viral identification rate was different (P = 0.012) according to air pollution. Specifically, the virus detection rate was 55.9% in the group of CAI 'D' with the highest air pollution. It was 24.4% in the group of CAI 'A' with the lowest air pollution. This pattern was clearly seen for influenza virus A (P = 0.042). When further analysis was performed with particulate matter (PM), the higher/lower the PM level, the higher/lower the virus detection rate. However, no significant difference was found in the analysis related to bacteria. CONCLUSION: Air pollution may make COPD patients more susceptible to respiratory viral infections, especially influenza virus A. Thus, on days with poor air quality, COPD patients need to be more careful about respiratory infections.

Differences in clinical significance of bronchodilator responses measured by forced expiratory volume in 1 second and forced vital capacity.

BACKGROUND: The 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. METHODS: We 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. RESULTS: Of 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. CONCLUSIONS: In 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.

Acute Eosinophilic Pneumonia after Combined Use of Conventional and Heat-Not-Burn Cigarettes: A Case Report.

Background: Acute eosinophilic pneumonia (AEP) is a rare acute respiratory disease accompanied by fever, shortness of breath, and cough. Although the pathogenesis of the disease is not yet established, the patient's condition improves with a rapid therapeutic response to systemic corticosteroids. Conventional cigarettes or heat-not-burn cigarettes are the most common cause of AEP among young people. Case Presentation: A 22-year-old woman with dyspnea, cough, and fever did not improve after visiting the local medical center and was admitted to the emergency room. The patient denied having any recent travel history or insect bites. She was treated with appropriate antibiotics according to the community acquired pneumonia, but there was no improvement. Chest radiography showed bilateral patches of pulmonary infiltration, and chest computed tomography revealed bilateral multifocal patchy consolidations with multiple small nodular ground-glass opacities and interlobular septal thickening. The bronchoalveolar lavage result was dominantly eosinophilic. The patient's condition improved rapidly after the use of intravenous methylprednisolone and then a change to oral methylprednisolone. Finally, the patient was hospitalized for 9 days, and the duration of use of methylprednisolone including outpatient visits was 14 days. Results: The early treatment of AEP yields a good prognosis, but since the symptoms of AEP are similar to those of infectious diseases such as community-acquired pneumonia, physicians should be meticulous in differentiating AEP from other diseases. Conclusions: Since AEP shows a good response to steroids, early detection using an appropriate diagnostic method is recommended. In addition, there should be strong education against smoking in any form.

Clinical Characteristics of Non-Smoking Chronic Obstructive Pulmonary Disease Patients: Findings from the KOCOSS Cohort.

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 .

Longitudinal changes in forced expiratory volume in 1 s in patients with eosinophilic chronic obstructive pulmonary disease.

BACKGROUND: Data on changes in lung function in eosinophilic chronic obstructive pulmonary disease (COPD) are limited. We investigated the longitudinal changes in forced expiratory volume in 1 s (FEV1) and effects of inhaled corticosteroid (ICS) in Korean COPD patients. METHODS: Stable COPD patients in the Korean COPD subgroup study (KOCOSS) cohort, aged 40 years or older, were included and classified as eosinophilic and non-eosinophilic COPD based on blood counts of eosinophils (greater or lesser than 300 cells/µL). FEV1 changes were analyzed over a 3-year follow-up period. RESULTS: Of 627 patients who underwent spirometry at least twice during the follow up, 150 and 477 patients were classified as eosinophilic and non-eosinophilic, respectively. ICS-containing inhalers were prescribed to 40% of the patients in each group. Exacerbations were more frequent in the eosinophilic group (adjusted odds ratio: 1.49; 95% confidence interval: 1.10-2.03). An accelerated FEV1 decline was observed in the non-eosinophilic group (adjusted annual rate of FEV1 change: - 12.2 mL/y and - 19.4 mL/y for eosinophilic and non-eosinophilic groups, respectively). In eosinophilic COPD, the adjusted rate of annual FEV1 decline was not significant regardless of ICS therapy, but the decline rate was greater in ICS users (- 19.2 mL/y and - 4.5 mL/y, with and without ICS therapy, respectively). CONCLUSIONS: The annual rate of decline in FEV1 was favorable in eosinophilic COPD compared to non-eosinophilic COPD, and ICS therapy had no beneficial effects on changes in FEV1.

A Multicenter Study to Identify the Respiratory Pathogens Associated with Exacerbation of Chronic Obstructive Pulmonary Disease in 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.

Clinical Characteristics of Patients with Post-Tuberculosis Bronchiectasis: Findings from the KMBARC Registry.

The clinical characteristics of patients with post-tuberculosis (TB) bronchiectasis have not been well evaluated. We enrolled 598 patients with bronchiectasis who participated in the Korean prospective bronchiectasis registry and compared the characteristics of post-TB bronchiectasis (19.7%) with post-infectious (19.6%), idiopathic (40.8%), and other (19.9%) bronchiectasis. The patients with post-TB bronchiectasis had a lower body mass index, higher rate of chronic obstructive pulmonary disease, and lower rate of asthma than those in the other groups. The patients with post-TB bronchiectasis had more upper lobe involvement, more severe radiological extent, and worse lung function than those in the other groups. Long-acting muscarinic antagonist/long-acting ß agonist use and mucolytics were more commonly used in the patients with post-TB bronchiectasis than those in the other groups, while inhaled corticosteroid/long-acting ß agonist was less commonly used. There were no significant intergroup differences in bronchiectasis severity scores except for FACED, the number of exacerbations, and quality of life. Post-TB bronchiectasis is characterised by reduced lung function and higher rates of mucolytic use when compared with other bronchiectasis; thus, adequate bronchodilator use and airway clearance techniques may alleviate symptom burden in this population.

Prognostic value of serial neutrophil-to-lymphocyte ratio measurements in hospitalized community-acquired pneumonia.

INTRODUCTION: Several serum inflammatory markers are associated with poor clinical outcomes in community-acquired pneumonia (CAP). However, the prognosis and early treatment response in hospitalized CAP patients based on serial neutrophil-to-lymphocyte ratio (NLR) measurement has never been investigated. METHODS: We performed a retrospective observational study for 175 consecutive patients hospitalized with CAP between February 2016 and February 2018. NLR, C-reactive protein (CRP) and procalcitonin levels were measured on admission day (D1) and on hospital day 4 (D4). The Pneumonia Severity Index (PSI) was also assessed on admission. The primary endpoint was all-cause death within 30 days after admission. The secondary endpoint was early treatment response such as intensive care unit (ICU) admission during hospitalization and clinical unstability on day 4. RESULTS: The 30-day mortality rate was 9.7%. In multivariate analysis, NLR D4 (OR: 1.11; 95% CI: 1.04-1.18; P = 0.003) and its incremental change (NLR D4/D1 >1) (OR: 7.10; 95% CI: 2.19-23.06; P = 0.001) were significant predictors of 30-day mortality. NLR D4 and its incremental change were significant predictors of ICU admission and clinical unstability on day 4 in multivariate analyses. Adding of incremental NLR change significantly improved the prognostic ability of the PSI. The additive value of incremental NLR change for the prognostic ability of the PSI was larger than that of incremental CRP change. CONCLUSION: Serial NLR measurement represents useful laboratory tool to predict the prognosis and early treatment response of hospitalized CAP patients.

Fibrinolysis with Lower Dose Urokinase in Patients with Complicated Parapneumonic Effusion.

BACKGROUND: Intrapleural urokinase is one of the most widely used fibrinolytic agents in the treatment of complicated parapneumonic effusion (CPPE). However, little research has been performed on the optimal urokinase dosage. The aim of this study was to evaluate the treatment efficacy of half dose urokinase compared with conventional dose urokinase. METHODS: We retrospectively enrolled 92 patients with CPPE or empyema who underwent intrapleural urokinase treatment at two tertiary hospitals. Patients received antibiotics, chest tube drainage, and other treatments as part of routine care. The primary outcome was the treatment success rate in the half dose urokinase group (50,000 IU daily for maximal 6 days) and the conventional dose urokinase group (100,000 IU daily). Treatment success was defined as clinical and radiological improvements without surgical treatment or re-admission within one month. RESULTS: Forty-four patients received half dose urokinase, whereas 48 patients were treated with conventional dose urokinase. Both groups were relatively well matched at baseline, excluding higher serum white blood cell count and higher empyema prevalence in the half dose urokinase group. The treatment success rate was not different between the two groups (p=0.048). There were no differences in the rate of in-hospital death and surgical treatment, hospitalization duration, and indwelling catheter duration. In the multivariate analysis, urokinase dose was not a predictor of treatment success. CONCLUSION: Half dose intrapleural urokinase is equally effective conventional dose urokinase in treating patients with CPPE or empyema.

Clinical Characteristics of Chronic Obstructive Pulmonary Disease in Female Patients: Findings from a KOCOSS Cohort.

Purpose: The prevalence of chronic obstructive pulmonary disease (COPD) in females has increased, changing the concept of COPD as a disease mostly limited to males. In this study, the clinical characteristics of COPD in females were investigated. Patients and Methods: The study was based on a multicenter cohort of COPD patients recruited from 54 medical centers in South Korea. Sex-based differences in general characteristics, exposure risk factors, depression scores, results of pulmonary function tests, COPD exacerbation, symptom scores, and radiologic findings were evaluated. Sex-related differences in the annual FEV1 change over 5 years were analyzed in a linear mixed model. Results: Of the 2515 patients enrolled in this study, 8.1% were female. Female patients who had a higher BMI and a lower level of education were less likely to be smokers, were more exposed to passive smoking/biomass, and were more depressed compared to males. The rates of bronchiectasis, previous childhood respiratory infection, and asthma were higher in females. Female patients also had more symptoms and a poorer exercise capacity than males, but no significant differences were observed in terms of exacerbations. Radiologic findings revealed that male patients had worse emphysema, and female patients had worse bronchiectasis, as determined based on chest X-ray and computed tomography findings. On pulmonary function tests, female patients had less obstruction and less annual FEV1 loss over 5 years. Conclusion: This study revealed differences in the clinical parameters between male and female patients with COPD, including general characteristics, disease characteristics, and clinical outcomes.

Correlation of epidermal growth factor receptor mutation status in plasma and tissue samples of patients with non-small cell lung cancer.

BACKGROUND: Somatic mutations of the gene encoding epidermal growth factor receptor (EGFR) are detected in approximately 30%-50% of patients with non-small cell lung cancers (NSCLC), so detection of EGFR mutation is the pivotal step of treatment in patients with advanced NSCLC. However, difficulty in obtaining sufficient tissue and bias from the heterogeneity of the tumor samples are the major obstacles. Although analyzing EGFR with circulating tumor DNA (ctDNA) in plasma is a breakthrough, accuracy is the problem in variable methods. Peptide nucleic acid (PNA) clamping-assisted fluorescence melting curve analysis (PANAMutyper®) is a novel and highly sensitive method of detecting EGFR mutation in tumor tissues. AIMS AND OBJECTIVES: This study was designed to evaluate PANAMutyper® for detecting EGFR mutation with ctDNA of patients with lung cancer. MATERIALS AND METHODS: EGFR mutation status detected by PNA clamp with tissue samples and by PANAMutyper® with ctDNA was compared. Tissue biopsy was done in 158 patients with lung tumor, in which 23 cases were excluded and 135 cases were enrolled. EGFR mutation rate was 23.0% (31/135) in overall patients. All the plasma samples of the cases with mutant EGFR in tissue samples were verified by an already known highly sensitive method of droplet digital polymerase chain reaction (ddPCR). RESULTS: The concordance rate of tissue and plasma samples was 91.9% (124/135). The sensitivity, specificity, negative predictive value, and positive predictive value were 64.5%, 100%, 90.4%, and 100%, respectively, according to the tissue samples as a standard. PANAMutyper® method was not inferior to ddPCR for the detection of EGFR mutation including T790M with ctDNA. These results suggest that the detection of EGFR mutation status using ctDNA in plasma by PANAMutyper® is a feasible test prior to tissue biopsy.

KMBARC registry: protocol for a multicentre observational cohort study on non-cystic fibrosis bronchiectasis in Korea.

INTRODUCTION: Despite the significant disease burden of bronchiectasis in Korea, no large-scale, representative prospective cohort studies have been conducted to evaluate the clinical characteristics of Korean patients with bronchiectasis, indicating an urgent need for cohort studies on bronchiectasis. METHODS AND ANALYSIS: The Korean Multicenter Bronchiectasis Audit and Research Collaboration (KMBARC) is a prospective, non-interventional observational cohort study on bronchiectasis in Korea. The inclusion criteria of this registry are as follows: (1) adult patients (aged ≥18 years) with or without respiratory symptoms (cough, chronic sputum and/or recurrent respiratory infection) and chest computed tomography revealing bronchiectasis affecting one or more lobes and (2) stable status at the time of registration: patients with bronchiectasis who were admitted for a respiratory aetiology can be enrolled at least 4 weeks after hospital discharge. The exclusion criteria are as follows: (1) bronchiectasis due to cystic fibrosis; (2) traction bronchiectasis associated with interstitial lung disease; (3) patients actively being treated for pneumonia, pulmonary tuberculosis or non-tuberculous mycobacterial infection; (4) patients who are unable or unwilling to provide informed consent; and (5) pregnant patients. Although the KMBARC questionnaires for baseline and annual follow-up data are similar to the European Multicentre Bronchiectasis Audit and Research Collaboration questionnaires, KMBARC has distinctive features such as use of Bronchiectasis Health Questionnaires, measurement with fatigue and depression scales, blood tests, use of consensus definition of exacerbations and information on emergency room or hospitalisation.We aim to recruit at least 1200 patients over the study period from more than 26 hospitals in South Korea. Patients will undergo a detailed baseline and yearly assessment for up to 5 years. The study objectives of the KMBARC registry are as follows: (1) uncovering the natural course of bronchiectasis; (2) aiding in establishing evidence-based bronchiectasis guidelines in Korea; and (3) encouraging and facilitating studies on bronchiectasis in Korea. ETHICS AND DISSEMINATION: This study received necessary approval from the Institutional Review Boards of all participating institutions. The Asan Medical Center Institutional Review Board gave overall approval for the study. Results will be disseminated via peer-reviewed publications and conference presentations. TRIAL REGISTRATION NUMBER: KCT0003088.

The Economic Effect of Early Management in Patients with Early Chronic Obstructive Pulmonary Disease: Results from a Population-Based Nationwide Survey.

PURPOSE: The economic effect of regular follow-up and early management in patients with early chronic obstructive pulmonary disease (COPD) has not yet been clarified. Therefore, this study aimed to estimate the economic effect of regular follow-up and early management in these patients. METHODS: Patients with early COPD were identified from the Korea National Health and Nutrition Examination Survey. We analyzed medical utilization and cost for 2 years without any missing data by using the Korean National Health Insurance data. Patients with routine healthcare maintenance were defined as, after diagnosis, those with regular visits to the hospital and receiving early management of COPD. RESULTS: Among 1204 patients with early COPD, the patients who were classified as the group with routine healthcare maintenance (69/146; 47.3%) and the group with intermittent healthcare user (79/1058; 7.5%) visited to hospital for the next 2 years. The patients with routine healthcare maintenance had lower cost of inpatient service and frequencies of emergency room (ER) visit and intensive care unit (ICU) admission than intermittent healthcare users (cost of inpatient service, $4595 vs. $4953 per person; ER visit, 7.2 vs. 11.5; ICU admission, 4.3 vs. 7.7). Even in patients with COPD and FEV1 ≥ 80, early intervention through follow-up reduced the cost of inpatient service because these patients could have had less severe acute exacerbations than intermittent healthcare users. CONCLUSION: Patients with early COPD, even those with FEV1 ≥ 80, need regular follow-up for early management and disease control as well as for reducing the socioeconomic burden of the disease.

Longitudinal change of FEV1 and inspiratory capacity: clinical implication and relevance to exacerbation risk in patients with COPD.

BACKGROUND AND OBJECTIVE: FEV1 is the gold standard for assessment of COPD. We compared efficacy of FEV1, inspiratory capacity (IC), and IC to total lung capacity (TLC) ratio in the evaluation of COPD and their association with exacerbation. METHODS: We analyzed the association of dyspnea severity, quality of life status, and lung function with lung function measurements and exacerbation risk in 982 patients enrolled in the Korea COPD Subgroup Registry and Subtype Research study. Exacerbation and longitudinal lung function change were evaluated in 3 years' follow-up. RESULTS: The FEV1, IC, and IC to TLC ratio showed comparable negative correlations with dyspnea severity and quality of life status, and positive correlation with exercise capacity. In patients with >2 events/year, annual rate of change in FEV1 and IC tended to decline more rapidly in those with FEV1 <50% than in those with FEV1 >50% (-14.46±19.40 mL/year vs 12.29±9.24 mL/year, P=0.213; -4.75±17.28 mL/year vs -78.05±34.16 mL/year, P=0.056 for FEV1 and IC, respectively), without significance. CONCLUSION: Longitudinal changes in IC and FEV1 were not significantly associated with exacerbation risk.

Clinical impacts of the classification by 2017 GOLD guideline comparing previous ones on outcomes of COPD in real-world cohorts.

PURPOSE: While GOLD classification has been revised, its clinical impacts on outcomes of COPD patients have not been widely evaluated in real-world cohorts. MATERIALS AND METHODS: According to 2007, 2013, and 2017 GOLD classifications, distribution and clinical characteristics of group-shifted patients and the risk of acute exacerbation were analyzed in combined Korean COPD cohorts. Future risk for annual moderate-to-severe exacerbation was estimated as incidence rate ratio (IRR) and compared by groups. RESULTS: Among 1,880 COPD patients, in GOLD 2017 classification, groups B and A were increased to 61.2% and 22.2% of total population, while group C was shrunken to 2.2% and patients with higher risk were decreased (16.6% in GOLD 2017 vs 44.7% in GOLD 2013). The kappa coefficient of agreement of both systems was 0.581 (agreement 71.7%). Groups B and D showed higher IRR of moderate-to-severe exacerbation than group A (IRR 2.4 and 5.3 respectively, P<0.001), whereas group C was not different from group A. When groups C and D were combined, the IRR for acute exacerbation for each group showed good linear trends (2.5 [1.6-3.7] for group B and 4.8 [3.0-7.7] for combined group [C+D], P<0.001). CONCLUSIONS: In the revised GOLD 2017 system, COPD patients with higher risk were much decreased in Korean cohorts, and group C was negligible in size and clinical impacts on expecting future exacerbation. Serial increase in the risk for exacerbation was more concrete and predictable when group C was combined with group D.

Is Severe and Long-lasting Linezolid-induced Optic Neuropathy Reversible?

Linezolid is a useful drug for treating drug-resistant tuberculosis. However, the associated toxicities, especially optic neuritis, are a major obstacle for its long-term use. We recently experienced a case of severe optic and peripheral neuropathy during the treatment of multidrug-resistant tuberculosis. The treatment continued for 12 months despite severe optic and peripheral neuropathy. At eight months after the discontinuation of the drug, the optic neuropathy recovered, but the peripheral neuropathy did not. Considering the grave prognosis of drug-resistant tuberculosis, the continuation of linezolid despite neurotoxicity under close observation may be a suitable option.

The Need for a Well-Organized, Video-Assisted Asthma Education Program at Korean Primary Care Clinics.

BACKGROUND: The purpose of this study was to assess the effect of our new video-assisted asthma education program on patients' knowledge regarding asthma and asthma control. METHODS: Adult asthmatics who were diagnosed by primary care physicians and followed for at least 1 year were educated via smart devices and pamphlets. The education sessions were carried out three times at 2-week intervals. Each education period lasted at most 5 minutes. The effectiveness was then evaluated using questionnaires and an asthma control test (ACT). RESULTS: The study enrolled 144 patients (mean age, 56.7±16.7 years). Half of the patients had not been taught how to use their inhalers. After participating in the education program, the participants' understanding of asthma improved significantly across all six items of a questionnaire assessing their general knowledge of asthma. The proportion of patients who made errors while manipulating their inhalers was reduced to less than 10%. The ACT score increased from 16.6±4.6 to 20.0±3.9 (p<0.001). The number of asthmatics whose ACT score was at least 20 increased from 45 (33.3%) to 93 (65.3%) (p<0.001). The magnitude of improvement in the ACT score did not differ between patients who received an education session at least three times within 1 year and those who had not. The majority of patients agreed to the need for an education program (95.8%) and showed a willingness to pay an additional cost for the education (81.9%). CONCLUSION: This study indicated that our newly developed education program would become an effective component of asthma management in primary care clinics.