IntroductionA low body mass index (BMI) is associated with increased mortality and low health-related quality of life in patients with COPD. The Asia-Pacific classification of BMI has a lower cutoff for overweight and obese categories compared to the World Health Organization (WHO) classification. The present study assessed patients with COPD among different BMI categories according to two BMI classification systems: WHO and Asia-Pacific.Patients and methodsPatients with COPD aged 40 years or older from the Korean COPD Subtype Study cohort were selected for evaluation. We enrolled 1,462 patients. Medical history including age, sex, St George’s Respiratory Questionnaire (SGRQ-C), the modified Medical Research Council (mMRC) dyspnea scale, and post-bronchodilator forced expiratory volume in 1 second (FEV1) were evaluated. Patients were categorized into different BMI groups according to the two BMI classification systems.ResultFEV1 and the diffusing capacity of the lung for carbon monoxide (DLCO) percentage revealed an inverse “U”-shaped pattern as the BMI groups changed from underweight to obese when WHO cutoffs were applied. When Asia-Pacific cutoffs were applied, FEV1 and DLCO (%) exhibited a linearly ascending relationship as the BMI increased, and the percentage of patients in the overweight and obese groups linearly decreased with increasing severity of the Global Initiative for Chronic Obstructive Lung Disease criteria. From the underweight to the overweight groups, SGRQ-C and mMRC had a decreasing relationship in both the WHO and Asia-Pacific classifications. The prevalence of comorbidities in the different BMI groups showed similar trends in both BMI classifications systems.ConclusionThe present study demonstrated that patients with COPD who have a high BMI have better pulmonary function and health-related quality of life and reduced dyspnea symptoms. Furthermore, the Asia-Pacific BMI classification more appropriately reflects the correlation of obesity and disease manifestation in Asian COPD patients than the WHO classification.

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 FEV 1 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 FEV 1 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.

Many patients suffering from asthma or COPD have overlapping features of both diseases. However, a phenotypical approach for evaluating asthma–COPD overlap syndrome (ACOS) has not been established. In this report, we examined the phenotypes in patients with ACOS. Patients diagnosed with ACOS between 2011 and 2015 were identified and classified into four phenotype groups. Group A was composed of patients who smoked <10 pack years and had blood eosinophil counts ≥300. Group B was composed of patients who smoked <10 pack years and had blood eosinophil counts <300. Group C was composed of patients who smoked ≥10 pack years and had blood eosinophil counts ≥300. Group D was composed of patients who smoked <10 pack years and had blood eosinophil counts <300. Clinical characteristics were analyzed and compared among groups. Comparisons were made among 103 ACOS patients. Patients in group D were oldest, while patients in group A were youngest. There were relatively more female patients in groups A and B; the majority of patients in groups C and D were male. The degree of airflow obstruction was most severe in group C. The rate of being free of severe exacerbation was significantly lower in group C than in the other groups. In this study, each ACOS phenotype showed different characteristics. The proportion of patients free of severe exacerbation differed significantly among groups. At this time, further studies on the phenotypes of ACOS are required.

Background: Acute exacerbation of interstitial lung disease (AE-ILD) causes clinically significant deterioration and has an extremely poor prognosis with high mortality. There are currently no demonstrated effective treatments. Recently, several studies reported the effectiveness of direct hemoperfusion with a polymyxin B-immobilized fiber column (PMX-DHP) in patients with AE-ILD as a potential therapy. This study describes the clinical effectiveness and safety of PMX-DHP in patients with AE-ILD. Methods:We retrospectively reviewed the medical records of 10 patients (11 episodes) with AE-ILD treated with PMX-DHP from January 2018 to June 2019. We compared laboratory and physiologic data of the ratio of partial pressure arterial oxygen to fraction of inspired oxygen (P/F ratio) and inflammatory markers before and after implementation of PMX-DHP.Results: Ten patients (11 episodes) were included according to the 2016 revised definition of acute exacerbation of idiopathic pulmonary fibrosis (IPF). Nine patients had IPF and one patient had fibrotic nonspecific interstitial pneumonia. Most patients (90.9%) were treated with a steroid pulse, and four patients (36.4%) were treated with an immunosuppressant. The median number of PMX-DHP cycles was 2, and the median duration of each cycle was 6 hours. After PMX-DHP, the mean P/F ratio improved (86 [range, 63-106] vs. 145 [86-260], P=0.030) and interleukin-6 and c-reactive protein decreased (79 [35-640] vs. 10 [5-25], P=0.018 and 14 [4-21] vs. 5 [2-6], P=0.019, respectively). The 30-day mortality rate was 27.3% and the 90-day mortality rate was 72.7%. There were no adverse events related to PMX-DHP treatment.Conclusions: PMX-DHP treatment improved P/F ratio and reduced inflammatory markers in AE-ILD patients.

Interstitial lung diseases (ILDs) are chronic, progressive, parenchymal lung diseases with high morbidity and mortality. In recent studies, the prevalence of obstructive sleep apnea (OSA) in patients with ILD has been reported to be high. However, the prevalence and predictive factors of OSA in Korean ILD patients are not well defined. Therefore, the aim of this study was to evaluate the prevalence and predictive factors of OSA in Korean patients with ILD. Clinical data from 86 patients with ILD enrolled from December 2017 to April 2019 at Haeundae-Paik Hospital, Busan, South Korea, were retrospectively analyzed. OSA was monitored with a level 4 portable device and defined as an apnea-hypopnea index of more than 5 per hour of sleep. The median follow-up period was 7 months. The mean age was 69.8 years, and 64% of participants were men. Among the ILDs, idiopathic pulmonary fibrosis (IPF) was the most common (66.3%), followed by connective tissue disease-associated ILD (16.3%) and cryptogenic organizing pneumonia (5.8%). Forty-six ILD patients (53.5%) were diagnosed with OSA, and IPF patients had OSA more frequently (64.9% vs. 31.0%, p = 0.003) than those with other ILDs. Older age (odds ratio [OR], 1.11, 95% CI 1.04-1.19, p = 0.002), higher body weight (OR 1.05, 95% CI 1.01-1.10, p = 0.012), and diabetes mellitus (OR 4.03, 95% CI 1.26-12.91, p = 0.019) were independent risk factors for OSA in the multivariable logistic regression analysis. In the multivariable Cox analysis, an IPF diagnosis was a significant risk factor for one-year mortality (hazard ratio [HR] 7.92, 95% CI: 1.01-61.83, p = 0.048) in ILD patients; however, OSA was not. In conclusion, half of Korean patients with ILD had OSA. Older age, higher body weight, and diabetes mellitus were risk factors for OSA in patients with ILD.

Idiopathic pulmonary fibrosis, which is one of the lung diseases, is quite rare but fatal in nature. The disease is progressive, and detection of severity takes a long time as well as being quite tedious. With the advent of intelligent machine learning techniques, and also the effectiveness of these techniques, it was possible to detect many lung diseases. So, in this paper, we have proposed a model that could be able to detect the severity of IPF at the early stage so that fatal situations can be controlled. For the development of this model, we used the IPF dataset of the Korean interstitial lung disease cohort data. First, we preprocessed the data while applying different preprocessing techniques and selected 26 highly relevant features from a total of 502 features for 2424 subjects. Second, we split the data into 80% training and 20% testing sets and applied oversampling on the training dataset. Third, we trained three state-of-the-art machine learning models and combined the results to develop a new soft voting ensemble-based model for the prediction of severity of IPF disease in patients with this chronic lung disease. Hyperparameter tuning was also performed to get the optimal performance of the model. Fourth, the performance of the proposed model was evaluated by calculating the accuracy, AUC, confusion matrix, precision, recall, and F1-score. Lastly, our proposed soft voting ensemble-based model achieved the accuracy of 0.7100, precision 0.6400, recall 0.7100, and F1-scores 0.6600. This proposed model will help the doctors, IPF patients, and physicians to diagnose the severity of the IPF disease in its early stages and assist them to take proactive measures to overcome this disease by enabling the doctors to take necessary decisions pertaining to the treatment of IPF disease.

Background: This study evaluated the efficacy and safety of pulmonary rehabilitation (PR) on functional performance, exercise-related oxygen saturation, and health-related quality of life among patients with idiopathic pulmonary fibrosis (IPF). Methods: A total of 25 patients with IPF (13 in the PR group and 12 in the non-PR group) were enrolled between August 2019 and October 2021 at Haeundae-Paik Hospital in the Republic of Korea. A cardiopulmonary exercise test (CPET), six-minute walk test (6MWT), pulmonary function test (PFT), Saint George’s Respiratory Questionnaire (SGRQ), muscle strength test, and bioelectrical impedance analysis were performed in each group at baseline and after eight weeks of PR. Results: The mean age was 68 years of age and most subjects were male. Baseline characteristics were similar between the two groups. The distance during 6MWT after PR was significantly improved in the PR group (inter-group p-value = 0.002). VO2max and VE/VCO2 slopes showed a significant difference after eight weeks only in the PR group, but the rate of change did not differ significantly from the non-PR group. Total skeletal muscle mass, PFT variables, and SGRQ scores did not differ significantly between the groups. Conclusions: PR improved exercise capacity, as measured using CPET and 6 MWT. Further studies in larger samples are needed to evaluate the long-term efficacy of PR in IPF patients.

Purpose Data regarding the relationship between microbiologic features and comorbidities in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) are limited. The aim of this study was to correlate microbiologic findings with comorbidities in patients with moderate to severe AECOPD. Patients and Methods This multicenter observational study included patients with AECOPD seen at 28 hospitals in South Korea between January 2015 and December 2018, and the data were retrospectively collected. Pathogens were examined in patients with either pulmonary or extrapulmonary comorbidities, and compared to those of patients without comorbidities. The relationship between pathogen type and the number of comorbidities was also evaluated. Results Bacterial infections (178 [37.2%] vs 203 [28.7%], p = 0.002) and co-infections with bacteria and viruses (65 [13.6%] vs 57 [8.1%], p = 0.002) were more prevalent in patients with pulmonary comorbidities. Bacterial pathogens (280 [34.7%] vs 101 [26.7%], p=0.006) were detected at a higher rate in patients with extrapulmonary comorbidities. Previous pulmonary tuberculosis (PTB), bronchiectasis, and diabetes mellitus were risk factors for bacterial infection, and congestive heart failure was a risk factor for bacterial and viral co-infection. As the number of comorbidities increased, the risk of bacterial infection increased considerably. Pseudomonas aeruginosa was more frequently identified in patients with previous PTB (57 [15.3%] vs 59 [7.4%], p < 0.001) and bronchiectasis (33 [19.6%] vs 83 [8.3%], p < 0.001). Conclusion AECOPD patients with comorbidities were more likely to experience infection-related exacerbations compared to those without comorbidities. As the overall number of comorbidities increased, the risk of bacterial infection increased significantly.