Sei Won Lee

• MD, PhD
• Professor at Asan Medical Center

Higher PM 2.5 levels, particularly in winter, are associated with worsened COPD outcomes, including increased exacerbations and poorer SGRQ-C scores.

Body mass index (BMI) is associated with chronic obstructive pulmonary disease (COPD) risk. We investigated the association between BMI and the risk of COPD among young individuals. Using the Korean National Health Information Database, we screened individuals aged 20–39 years who participated in the national health examination between 2009 and 201...

Background Diabetes mellitus (DM) and alcohol consumption are risk factors for tuberculosis (TB). We investigated the association between alcohol consumption and TB development in individuals with type 2 DM (T2DM). Methods Individuals who underwent the national health examination during 2009–2012 were screened using the Korean National Health Info...

Background The association between metabolic syndrome (MetS) and chronic obstructive pulmonary disease (COPD) has not been studied well, particularly in young individuals. We investigated the risk of COPD development in young individuals based on MetS and its components. Methods We used the Korean National Health Information Database to identify 6...

Although smoking is an established risk factor for Mycobacterial infection, the association between smoking and nontuberculous mycobacterial pulmonary disease (NTM-PD) remains unclear. We evaluated the association between smoking and NTM-PD and tuberculosis (TB) using a population-based South Korean nationwide cohort. Using the Korean National Heal...

Background Particulate matter with a diameter of < 2.5 μm (PM2.5) influences gene regulation via DNA methylation; however, its precise mechanism of action remains unclear. Thus, this study aimed to examine the connection between personal PM2.5 exposure and DNA methylation in CpG islands as well as explore the associated gene pathways. Methods A to...

Background Low socioeconomic status is a risk factor for chronic obstructive pulmonary disease (COPD); however, the association between low household income and COPD in young populations remains unclear. Methods We screened individuals aged 20–39 years who underwent the national health examination between 2009 and 2012 using the Korean National He...

This study investigated the correlation between the individual chemical constituents of particulate matter 2.5 μm (PM2.5) and respiratory parameters as well as the living environment and daily behaviors in patients with chronic obstructive pulmonary disease (COPD). Data were obtained from prospective COPD panel conducted in South Korea. Following c...

Background Exposure to noxious particles, including cigarette smoke and fine particulate matter (PM2.5), is a risk factor for chronic obstructive pulmonary disease (COPD) and promotes inflammation and cell death in the lungs. We investigated the combined effects of cigarette smoking and PM2.5 exposure in patients with COPD, mice, and human bronchia...

Rehabilitation improves symptoms, quality of life, and survival in patients with chronic respiratory or cardiovascular disease. We evaluated smartphone application-based rehabilitation programs for patients with chronic respiratory or cardiovascular diseases. This was a single-center prospective single arm study. Participants underwent smartphone a...

Background Pulmonary rehabilitation is well known to improve clinical symptoms (including dyspnea), quality of life, and exercise capacity in patients with chronic obstructive pulmonary disease (COPD). However, researchers have reported difficulties in practicing center-based pulmonary rehabilitation. Recently, mobile app–based pulmonary rehabilita...

Superoxide dismutase (SOD) can convert active oxygen to oxygen or hydrogen peroxide, and recent research has suggested that it can protect against lung damage and fibrosis. Clinical applications based on SOD remain limited however due to costs and low stability. We here investigated a potential new therapeutic delivery system for this enzyme in the...

The interaction between the microbial environment and the host is important for immune homeostasis. Recent research suggests that microbiota dysbiosis can be involved in respiratory diseases. Emphysema is a chronic inflammatory disease, but it is unclear whether dysbiosis caused by antibiotics can affect disease progression. Here, we tried to eluci...

Background Diet has a crucial role in the gut microbiota, and dysbiosis in the gut and lungs has been suggested to be associated with chronic obstructive pulmonary disease. We compared the diet, microbiome and metabolome between asymptomatic smokers and those with emphysema. Methods We enrolled 10 asymptomatic smokers with preserved lung function...

Particulate matter (PM) is a major air pollutant that has led to global health concerns and can cause and exacerbate chronic obstructive pulmonary disease (COPD). We asked patients with COPD to complete a detailed questionnaire about their lifestyle practices to reduce PM2.5 exposure and analyzed the relationship between ambient PM2.5 concentration...

Background: The natural course of chronic obstructive pulmonary disease (COPD) is characterized by symptom exacerbation and quality-of-life reduction. Therefore, symptoms should be properly assessed. Some studies have demonstrated a weak correlation between cardiopulmonary exercise testing (CPET) parameters and symptoms in patients with COPD; howe...

Background: The prevalence of asthma has increased in many countries. However, whether asthma prevalence may only be true in a specific age band is not well known. Thus, we analyzed the increase in asthma prevalence according to age band and analyzed the related factors. Methods: We analyzed the trend of asthma prevalence according to 10-year ag...

Background: Codeine has been long used as an antitussive drug in several countries. However, a prescription pattern of codeine, such as dose or treatment duration, has not been reported in detail. Furthermore, there is few scientific evidence on the efficacy and safety. We aimed to examine codeine prescription pattern and explore treatment respons...

Background Low-dose chest CT screening is recommended for smokers with the potential for lung function abnormality, but its role in predicting lung function remains unclear. Purpose To develop a deep learning algorithm to predict pulmonary function with low-dose CT images in participants using health screening services. Materials and Methods In thi...

Mycobacterium tuberculosis (MTB) is a communicable disease and still remains a threat to common health. Thus, early diagnosis and treatment are required to prevent the spread of infection. Despite the recent advances in molecular diagnostic systems, the commonly used MTB diagnostic tools are laboratory-based assays, such as mycobacterial culture, M...

Purpose: Although the coexistence of asthma and bronchiectasis is common, the impacts of asthma on bronchiectastic patients (BE) have not been well evaluated because this issue using bronchiectasis cohorts has been investigated in only a few studies. Methods: In the present study, 598 patients who were prospectively enrolled in the Korean bronch...

Background Chronic obstructive pulmonary disease (COPD) is a well-known risk factor for postoperative pulmonary complications (PPCs), necessitating careful preoperative evaluation in patients undergoing lung resection surgery. The risk of PPCs in patients with COPD may vary with severity of symptoms, and the COPD Assessment Test (CAT) score is comm...

Background Air pollution has become a significant public health concern. During exercise, many physiological factors are thought to increase the effects of air pollution. Air pollution most affects lung function and respiratory symptoms. We investigated the association between lung function, respiratory symptoms, and air pollutant concentration wit...

Background The prognostic value of bronchoalveolar lavage (BAL) fluid analysis in non-human immunodeficiency virus (HIV)-infected patients with Pneumocystis jirovecii pneumonia (PJP) has not been well elucidated. We aimed to investigate the prognostic implication of BAL fluid analysis in non-HIV patients with PJP. Methods The data of 178 non-HIV p...

Background: Incremental shuttle walking tests (ISWT) are regarded as valuable alternatives to 6-min walking tests (6MWT) and cardiopulmonary exercise tests (CPET) owing to the maximal and externally paced loading. This study investigated the validity and reliability of ISWT by analyzing the correlation of the distances of two field tests with peak...

The development of a rapid, accessible, and highly sensitive diagnostic tool is a major challenge in the control and management of tuberculosis. Gene-based diagnostics is recommended for the rapid diagnosis of pulmonary tuberculosis (PTB), but its sensitivity, such as Xpert MTB/RIF assay (Xpert), drops in cases with a low bacterial load.

Lung cancer is the primary cause of cancer-related deaths worldwide. Recently, although the microbiome has emerged as the key modulator of the carcinogenesis, it has not been evaluated in lung cancer. Here, we evaluated the microbial composition of lung cancer tissues according to the histologic type and genetic mutation, compared it with that of t...

Background: Maximal oxygen uptake (VO₂ max) is a useful index to assess exercise capacity. However, there is no reference value for Koreans. This study aimed to compare actual VO₂ max and predicted VO₂ max using exercise capacity equations in Korean subjects. Methods: This retrospective study enrolled 383 patients who underwent cardiopulmonary e...

The comparative effectiveness of different inhaler therapies in mild-to-moderate asthma remains unclear. To assess this, we performed a systematic review and network meta-analysis of randomized controlled trials on the use of inhalers for mild-to-moderate asthma by searching PubMed, Cochrane, and Embase. A total of 29 trials including 43,515 patien...

Background: Most knowledge on cough epidemiology was obtained from questionnaire surveys of general populations or small focused studies of patients visiting specialist clinics. Routinely collected data (RCD) from electronic health records (EHR) are useful sources for studying disease epidemiology, but their use was limited in chronic cough. The pr...

Background With the emergence of bronchiectasis as a common respiratory disease, epidemiological data have accumulated. However, the prevalence and impact of psychological comorbidities were not sufficiently evaluated. The present study examined the prevalence of depression and its associated factors in patients with bronchiectasis. Methods This s...

Background: A diagnostic bundle for bronchiectasis in South Korea is necessary because the etiologies of bronchiectasis and related diseases vary significantly among different regions and ethnicities. Methods: A modified Delphi method was used to develop expert consensus statements on a diagnostic bundle for bronchiectasis in South Korea. Initia...

Background It is difficult to diagnose tuberculosis (TB), particularly sputum-scarce pulmonary TB and extrapulmonary TB, using conventional diagnostic tests. Since these cases require additional invasive procedures to obtain appropriate specimens, new non-invasive diagnostic tests are needed. Plasma cell-free DNA (cfDNA) detection has gained intere...

Despite the burden of bronchiectasis, there is little data from South Korea regarding asymptomatic bronchiectasis. We aimed to investigate the prevalence of bronchiectasis based on computed tomography (CT) findings, with emphasis on asymptomatic bronchiectasis (CT-proven) and its related factors. We analysed data of individuals who underwent chest...

Objective: Emphysema and small-airway disease are the two major components of chronic obstructive pulmonary disease (COPD). We propose a novel method of quantitative computed tomography (CT) emphysema air-trapping composite (EAtC) mapping to assess each COPD component. We analyzed the potential use of this method for assessing lung function in pat...

Cough is the most common respiratory symptom that can result from various causes, and is a major clinical problem that reduces patients' quality of life. Thus, clinical guidelines for the treatment of cough were established in 2014 by the cough guideline committee under the Korean Academy of Tuberculosis and Respiratory Diseases. From October 2018...

Dietary fiber functions as a prebiotic to determine the gut microbe composition. The gut microbiota influences the metabolic functions and immune responses in human health. The gut microbiota and metabolites produced by various dietary components not only modulate immunity but also impact various organs. Although recent findings have suggested that...

Background Which patients should receive dual therapy as initial treatment for chronic obstructive pulmonary disease (COPD) is only loosely defined. We evaluated if a lower forced expiratory volume in 1 s (FEV1) identifies a population more likely to benefit from dual therapy than monotherapy among group B COPD patients in whom Global initiative fo...

Diet is a health-related factor that can modify lung function. This study hypothesized that the change in age-related dietary intake affects lung function. The subjects who undertook a dietary assessment and spirometry in 2012 and 2017, were retrospectively collected in a health screening center. Dietary intakes were directly evaluated using food f...

Background Maintenance of inhaled corticosteroids (ICSs) is recommended in adults with asthma. However, adherence rates in patients with mild asthma and side effects of long-term ICS use can lead to withdrawal. Objective To analyze the real-world outcomes of ICS withdrawal by analyzing data from the Korean National Health Insurance database. Meth...

Purpose Pulmonary rehabilitation (PR) is a well-established treatment for chronic obstructive pulmonary disease (COPD). The standard protocol for PR requires frequent hospital visits, which can be difficult for patients. We performed this study to assess whether unsupervised home-based PR (HBPR) is effective for patients with COPD. Patients and Me...

Background/aims: Although international guidelines for bronchiectasis management have been published in Western countries, there is a lack of data about their application in Asian populations including patients with different phenotypes. We aimed to investigate the current status of bronchiectasis management in Asian populations. Methods: A nati...

Objective: To assess the regional ventilation in patients with asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) using xenon-ventilation dual-energy CT (DECT), and to compare it to that in patients with COPD. Materials and methods: Twenty-one patients with ACOS and 46 patients with COPD underwent xenon-ventilation DECT....

Background The Bronchiectasis Health Questionnaire (BHQ) is a simple and repeatable, self-reporting health status questionnaire for bronchiectasis. We have translated the original version of the BHQ into Korean using a standardized methodology. The purpose of this study was to assess the validity of the Korean version of the BHQ (K-BHQ) with Korean...

Objective: Patients with chronic obstructive pulmonary disease (COPD) are known to be at risk of osteoporosis. The purpose of this study was to evaluate the association between thoracic vertebral bone density measured on chest CT (DThorax) and clinical variables, including survival, in patients with COPD. Materials and methods: A total of 322 pa...

Background: Pulmonary rehabilitation (PR) is a well-established treatment for chronic obstructive pulmonary disease (COPD). The standard protocol for PR requires frequent hospital visits, which can be difficult for patients. We performed this study to assess whether unsupervised home-based PR (HBPR) is effective for patients with COPD. Methods: Thi...

Background: Although the association of hyperuricemia with an increased risk of mortality has been demonstrated in the context of acute exacerbation of chronic obstructive pulmonary disease (COPD), the long-term outcomes of hyperuricemia have not been studied in the case of stable COPD. Methods: We retrospectively analyzed baseline data of 240 m...

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 Br...

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive diagnostic for mediastinal and hilar lymphadenopathy/mass. This study investigated fever incidence and associated risk factors after EBUS-TBNA in 6336 patients who underwent EBUS-TBNA at Asan Medical Center from October 2008 to February 2018. Bronch...

Background: The prevalence and disease burden of bronchiectasis in comparison to those of chronic obstructive pulmonary disease (COPD) have not been well elucidated using a nationally representative database. Methods: We compared respiratory symptoms, physical activity, quality of life, and socioeconomic status in subjects with bronchiectasis vers...

Background: Pulmonary functions are interpreted using predicted values from reference equations that vary with ethnicity, gender, age, height, and weight. The universally used Choi's reference equations are not validated for Korean populations, and the purpose of this study was to validate them and develop new reference equations. Methods: Subje...

Background/aims: Few studies have attempted to interpret unusually high predicted pulmonary function test results. This study aimed to investigate the demographic features of patients with an unusually high predicted pulmonary function. Methods: The demographic data of subjects who underwent pulmonary function testing at a tertiary referral hosp...

Purpose To assess changes in regional ventilation (V), perfusion (Q), and V-Q mismatch in patients with chronic obstructive pulmonary disease (COPD) after pharmacologic treatment using combined xenon-enhanced V and iodine-enhanced Q dual-energy CT (DECT). Patients and methods Combined V and Q DECT were performed at baseline and after three-month p...

BACKGROUND: In patients with chronic obstructive pulmonary disease (COPD), the plasma fibrinogen level is associated with a decline in lung function and exacerbation of COPD. High blood eosinophil count is also associated with exacerbation of COPD in some studies but not others.OBJECTIVE: To investigate the associations between clinical phenotypes...

Background: Although vitamin D deficiency is prevalent in patients with chronic obstructive pulmonary disease (COPD), the influence of vitamin D deficiency on COPD has not been fully established. Moreover, the inflammation process is associated with vitamin D deficiency in the general population. Therefore, this study aimed to determine whether cl...

Objective: The absence of collateral ventilation (CV) is crucial for effective bronchoscopic lung volume reduction (BLVR) with an endobronchial valve. Here, we assessed whether CT can predict the Chartis™ results. Materials and methods: This study included 69 patients (mean age: 70.9 ± 6.6 years; 66 [95.7%] males) who had undergone CT to assess...

Background: The utility of computed tomography (CT) in the differential diagnosis of patients with chronic obstructive pulmonary disease (COPD) exacerbation remains uncertain. However, due to the low cost associated with CT scan along with the impact of Koreas' health insurance system, there has been a rise in the number of CT scans in the patient...

Background Frequent development of adverse events and consequent low adherence are major barriers in the wide use of roflumilast. Asian patients may be more susceptible to adverse events due to low BMI. In this study, we aimed to determine if a dose-escalation strategy is useful to improve the drug adherence rate. Methods This was a randomized, pr...

Bronchial thermoplasty is a nonpharmacological treatment for severe asthma that delivers thermal energy to the bronchial walls and reduces hypertrophied smooth muscle mass. Previous studies have shown its efficacy and safety, resulting in approval from the Food and Drug Administration in 2010. In Korea, the first bronchial thermoplasty was carried...

Background This cohort study of patients with chronic obstructive pulmonary disease (COPD) was performed to evaluate the status of inhaled corticosteroid (ICS) prescriptions following the 2017 revision of the Global Initiative for Chronic Obstructive Lung Disease guidelines. Methods A total of 1144 patients from the Korean Obstructive Lung Disease...

Purpose: We aimed to investigate the natural history of non-cavitary nodular bronchiectatic (NC-NB) Mycobacterium avium complex (MAC) lung disease (LD). Methods: Among all patients diagnosed with NC-NB MAC LD between March 2000 and December 2013, 551 patients who were followed until December 2017 were enrolled at a tertiary referral center in So...

Although it is known that in vitro minimal inhibitory concentrations (MICs) of rifampin and ethambutol are poorly correlated with clinical response in Mycobacterium avium complex lung disease (MAC-LD), its evidence is limited. This study investigated the association between treatment outcome and in vitro MICs of rifampin and ethambutol in patients...

Background: Although aminoglycosides are recommended for cavitary Mycobacterium avium complex lung disease (MAC-LD), the optimal duration of treatment is unclear. We investigated the association between duration of aminoglycoside treatment and outcomes in cavitary MAC-LD. Methods: Among patients diagnosed with macrolide-susceptible cavitary MAC-...

Background: Under the Food and Drug Administration's drug development tool qualification program, fibrinogen is the first biomarker drug development tool used in chronic obstructive pulmonary disease (COPD). However, the correlation between fibrinogen and exacerbations among Korean patients with COPD remains unclear. Methods: In this retrospecti...

Background and objective Despite the ongoing intense debate on the definition of airflow limitation by spirometry in the elderly population, there have only been few studies comparing the fixed ratio and the Z-score of forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) in terms of long-term mortalities. In this study, we aimed...

Comparison of the prediction performance of the fixed ratio and the Z-score of FEV1/FVC for 10-year all-cause mortality (A), 10-year respiratory mortality (B), and 10-year COPD mortality (C) in the male elderly population. Note: Youden index is defined as sensitivity + specificity − 1. Abbreviations: FEV1, forced expiratory volume in 1 second; FVC,...

Comparison of the prediction performance of the fixed ratio and the Z-score of FEV1/FVC for 10-year all-cause mortality (A), 10-year respiratory mortality (B), and 10-year COPD mortality (C) in the elderly population using the reference values from GLI. Note: Youden index is defined as sensitivity + specificity − 1. Abbreviations: FEV1, forced expi...