BACKGROUND:Exercise-induced desaturation (EID) during the 6-minute walk test (6MWT) is an established marker of adverse outcomes in patients with chronic obstructive pulmonary disease (COPD). We therefore sought to develop a screening-oriented machine learning approach to identify patients at increased risk of EID. METHODS:We analyzed data from the nationwide, multicenter Korea COPD Subgroup Study (KOCOSS). EID was defined as peripheral oxygen saturation (SpO2) < 90% with a decrease of ≥ 4%p. The cohort was stratified into training (80%) and test (20%) sets. Candidate predictors were selected using the Boruta algorithm, and models were developed using multivariable logistic regression (MLR), extreme gradient boosting (XGB), random forest (RF), and support vector classification (SVC), with a screening-oriented threshold strategy prioritizing sensitivity. RESULTS:Among 1,788 patients with COPD, 185 (10.3%) exhibited EID. All models showed high area under the precision-recall curve (PR-AUC) during internal validation. Predictors selected by the Boruta algorithm included body mass index, COPD Assessment Test, St. George's Respiratory Questionnaire-C, mental health indicators, pulmonary function parameters, X-ray-identified bronchiectasis, and hemoglobin level. In the independent test set, PR-AUC declined across models while calibration metrics showed modest differences between datasets. The XGB model achieved the highest sensitivity in internal validation and its sensitivity and specificity remained relatively stable in the test set. Baseline SpO2 and diffusion capacity of the lung for carbon monoxide were the most influential predictors. CONCLUSION:A screening-oriented machine learning approach using routinely available variables may facilitate targeted referral for the 6MWT in COPD.

Background:Gait speed, a key component of exercise capacity, has been underutilised in COPD, despite its prognostic potential. We aimed to evaluate the association between gait speed and clinical outcomes in COPD using 3-year longitudinal data from the Korean COPD Subgroup Study cohort. Methods:Poor gait speed (<1.0 m·s-1) was defined by usual pace during the 6-min walk test per Asian Working Group for Sarcopenia 2019 criteria. Lung function, symptoms, acute exacerbations (AEs) and mortality were compared between gait speed groups. Analyses included propensity score-matching, quartile classification, subgroup analyses and longitudinal trajectory modelling using random coefficient models. Results:Among 2063 participants, poor gait speed (n=831, 40.3%) was associated with older age, higher symptom burden and more previous AEs despite similar lung function. This group showed higher AE risk and frequency than the normal-speed group: adjusted odds ratios 1.37-1.45 for moderate and 1.64-1.65 for severe AEs; adjusted incidence rate ratios 1.24-1.36 for moderate and 1.63-1.86 for severe AEs. The 3-year mortality was significantly higher in the poor-gait-speed group (adjusted hazard ratio 2.30, 95% CI 1.42-3.73). Longitudinally, the poor-gait-speed group demonstrated persistently worse COPD Assessment Test (CAT) and St George's Respiratory Questionnaire for COPD scores at baseline, with modest CAT worsening over time (+0.44 point/year, p=0.01), while lung function decline was similar. Conclusions:Gait speed provides a simple, integrative marker that independently predicts exacerbation risk, mortality and symptom progression in COPD.

Background:Chronic obstructive pulmonary disease (COPD) is associated with cardiovascular disease and chronic kidney disease, but with conflicting estimates. We aimed to quantify the association of COPD and incident cardiovascular diseases, chronic kidney disease and death. Methods:In this systematic review and meta-analysis, we searched MEDLINE and Embase for case-control studies reporting associations between COPD and cardiovascular diseases, chronic kidney disease and death from database inception until 15 April 2026. Two reviewers independently extracted study characteristics and reported risk ratios of incident outcomes associated with COPD, specifically: atrial fibrillation and flutter, ventricular fibrillation and tachycardia, myocardial infarction, ischaemic stroke, heart failure, peripheral arterial disease, chronic kidney disease, cardiovascular mortality and all-cause mortality. Pooled estimates were obtained using random-effects models with restricted maximum likelihood estimation as substantial heterogeneity was anticipated. Ten sensitivity analyses stratifying studies by design, follow-up duration, region, clinical context, sample size, publication date, COPD ascertainment, leave-one-out, ratio adjustment and risk of bias, subgroup analyses by age and risk group were undertaken, and subsequent univariate and multivariate meta regression was performed. Study quality was assessed using the risk of bias in non-randomised follow-up studies of exposure effects (ROBINS-E) tool, and certainty of evidence was assessed using Grading of Assessment, Evaluation, Development and Evaluation (GRADE) criteria. Risk of publication bias was assessed using funnel plots and Egger's regression. This review was registered on PROSPERO (CRD42025639084). Findings:Of 140 case-control studies including 30,144,481 patients (3,062,712 with COPD) with median follow -up duration of 3.0 years (IQR 1.0-5.2), COPD was associated with increased risk of heart failure (risk ratio [RR] 2.33, 95% CI 1.78-3.06), ventricular tachycardia (2.05, 1.27-3.31), peripheral arterial disease (1.99, 1.49-2.65), heart failure hospitalisation (1.78, 1.28-2.47), chronic kidney disease (1.65, 1.25-2.16), all-cause mortality (1.55, 1.42-1.70), cardiovascular mortality (1.55, 1.33-1.82), myocardial infarction (1.47, 1.28-1.68), ischaemic stroke (1.38, 1.18-1.62), and atrial fibrillation (1.38, 1.19-1.61) when compared to those without COPD. Despite substantial heterogeneity for all outcomes, associations between COPD and outcomes were broadly consistent across sensitivity analyses. Interpretation:COPD is associated with an increased risk for a range of incident cardiovascular diseases, chronic kidney disease and mortality. The impact of current and novel treatments on a broader range of cardiovascular and kidney outcomes in patients with COPD requires prospective randomised assessment. Funding:The British Heart Foundation.

BACKGROUND:The way in which risk predictors combine and contribute to severe asthma exacerbations may differ between clinical trials and real-world settings. RESEARCH QUESTION:How do the interactive pathways of risk predictors leading to severe asthma exacerbations compare under clinical trials vs real-world settings? STUDY DESIGN AND METHODS:The analysis involved 345 patients with severe asthma from the placebo arms of 2 international randomized controlled trials (RCTs), compared with 6,814 biologic-naïve patients from the International Severe Asthma Registry (ISAR). Sixteen key risk predictors, including demographics, biomarkers, lung function, health care use, exacerbation history, long-term oral corticosteroid use, asthma control, and nasal polyps, were covered. The outcome was the occurrence of severe asthma exacerbations over the 365 days after study enrollment. Bayesian networks (BNs), obtained from machine learning combined with expert knowledge, elucidated significant interplay processes of risk predictors that led to severe asthma exacerbations. External validation was performed in each cohort. RESULTS:The RCTs revealed 44 significant arcs (ie, probabilistic interdependency) between 16 risk factors, whereas the ISAR showed 170. Despite this difference, the main downstream prediction pathways were consistent across both settings, with 2 key pathways: total serum IgE level influenced blood eosinophils to predict future severe exacerbations, and severe exacerbation history directly predicted future severe exacerbations. In external validation, RCT-BN generalized well to ISAR patients (area under the receiver operating characteristic curve, 0.68), whereas ISAR-BN underperformed in RCT patients (area under the receiver operating characteristic curve, 0.50), and ISAR-BN demonstrated better calibration. INTERPRETATION:Our results show that the core pathways predicting severe asthma exacerbations were similar in both RCTs and real-world settings, with comparable predictive performance.

Introduction:Some individuals with airflow obstruction later show normalized spirometric values, but the clinical implications of this phenomenon in the general population are unclear. Methods:Using data from the Korean Genome and Epidemiology Study (KoGES), we examined the characteristics and prognosis of individuals with normalized airflow obstruction (NO), defined as FEV1/FVC <0.7 at baseline that normalized to ≥0.7 during follow-up. Results:Between 2000 and 2006, 4,807 participants were classified as NO (n=242), fixed obstruction (FO; persistent FEV1/FVC <0.7; n=277), or normal (FEV1/FVC ≥0.7 throughout; n=4,288). Over eight years of follow-up (2007-2014), the NO group contained more men, current smokers, and individuals with lower body mass index than the normal group and showed intermediate lung function between FO and normal groups. Annual FEV1 decline was similar across groups (-48.8 mL/year normal; -48.3 mL/year NO; -45.8 mL/year FO). However, by the end of the 12-year follow-up period, 37.2% of participants in the NO group developed airflow obstruction, with a 4.22-fold higher risk compared with the normal group (95% CI 3.26-5.46). Findings were consistent in a sensitivity analysis excluding individuals with excessive lung function variability. (HR 7.41, 95% CI 5.45-10.07). Discussion:These findings indicate that NO may represent a distinct and dynamic spirometric phenotype associated with increased risk of future airflow obstruction and highlight the need for early identification and preventive strategies in at-risk populations.

Purpose:Time to biologic initiation for the treatment of severe asthma (SA) is affected by many factors, including ease of access to biologics, which is often subject to approval by regulatory authorities and reimbursement criteria by relevant agencies. We investigated the association between ease of biologic access (using the biologic accessibility score [BACS] as a proxy) and post-biologic asthma outcomes, including remission. Methods:This ecological study, using data from CHRONICLE (a US severe asthma registry), the International Severe Asthma Registry (ISAR), and the Optimum Patient Care Research Database (OPCRD), included patients with SA from 21 countries. Associations at the country level, between BACS, a composite score of prescription criteria for biologics in SA, and the proportion of patients with a favorable asthma outcome 1-year post-biologic in each setting (ie ISAR country or in the CHRONICLE or OPCRD datasets) were tested. Several definitions of favorable outcome were used, including proportion of patients who achieved clinical remission (defined using 2, 3 and 4 domains), experienced no exacerbations, had well- or partly controlled asthma, a percent predicted forced expiratory volume in 1 second (ppFEV1) or percent predicted peak expiratory flow rate (ppPEFR) ≥80%, and no long-term oral corticosteroid (LTOCS) use. Results:A total of 9,183 patients were included. A higher BACS (as a proxy of easier access to biologics) was associated with a higher likelihood of achieving clinical remission (p≤0.001), no exacerbations (p<0.001), well- or partly controlled asthma (p=0.047), a ppFEV1 or ppPEFR ≥80% (p=0.004), and no need for LTOCS (p=0.045) 1 year post-biologic initiation. Conclusion:Easier access to biologics for patients with SA, a prerequisite for shorter time-to-initiation, was associated with a greater probability of achieving clinical remission and other favorable asthma outcomes. Initiating biologics earlier in the asthma disease course may help unlock greater therapeutic potential in SA. These findings warrant confirmation in additional studies to further establish the causal relationship between biologic accessibility, timing of initiation, and clinical outcomes in SA.

BACKGROUND:Severe asthma (SA) is associated with frequent exacerbations and high treatment costs. OBJECTIVES:To develop and validate an individualized risk calculator for severe exacerbations in SA, and evaluate its clinical utility for guiding personalized clinical decisions. METHODS:Patients with SA were identified from combined data from the International Severe Asthma Registry (2015-2022) and NOVEL observational longiTudinal studY (2016-2023) across 30 countries and regions. The prediction end point was the 12-month risk of 1 or more or 2 or more severe exacerbations. Using expert input and Bayesian network analysis, 11 routinely measured predictors were identified, measured within the past 12 months. A mixed-effects, zero-inflated negative binomial model was developed, adjusting for between-country variability and biologic drop-in effects. Internal-external cross-validation was performed using the natural clustering by country settings. RESULTS:Data from 9911 patients with SA were used. Essential predictors included age, sex, past 12-month severe exacerbations, asthma control, chronic rhinosinusitis, FEV1 to forced vital capacity ratio, percent predicted FEV1, blood eosinophils, fractional exhaled nitric oxide, and long-term oral corticosteroid and macrolide use. The model also adapted setting-specific baseline risks. In the internal-external cross-validation, across broad geographical and health care variability, the model showed excellent calibration and informative, generalizable discrimination (pooled area under the time-dependent receiver-operating characteristics curve of 0.63 [95% CI, 0.60-0.66] for ≥1 and 0.68 [95% CI, 0.64-0.72] for ≥2 exacerbations). Decision curve analysis showed clear net benefit across risk thresholds. CONCLUSIONS:The Risk of Exacerbation in Severe Asthma model quantifies SA exacerbation risk using routinely available predictors and demonstrates potential clinical utility.

Background The Rapid Cough Questionnaire (RCQ) is a simplified three-item instrument developed as a pragmatic alternative to the Leicester Cough Questionnaire (LCQ). However, its performance across diverse respiratory diseases, particularly structural lung diseases, has not been sufficiently validated. This study evaluated the performance of the RCQ across major respiratory disease subgroups.Methods A total of 300 adult patients with chronic cough were prospectively enrolled from multiple respiratory centres. Participants completed five cough-specific instruments: Numeric Rating Scale (NRS), Cough Symptom Score (CSS), COugh Assessment Test (COAT), LCQ and RCQ. Construct validity was evaluated using correlation analyses across disease subgroups, including chronic obstructive pulmonary disease, asthma, idiopathic pulmonary fibrosis (IPF) and bronchiectasis.Results The RCQ showed strong correlations with the LCQ (r=0.93), COAT (r=-0.75), CSS (r=-0.62) and NRS (r=-0.59). These relationships remained robust among all aetiologies, with the correlation coefficients between RCQ and LCQ exceeding 0.88 in each subgroup. Bland-Altman plots and an intraclass correlation analysis indicated a high level of concordance between the RCQ and LCQ scores. The RCQ aligned closely with multidimensional symptom burden and maintained strong correlation with the LCQ even for IPF, where LCQ correlations with unidimensional tools (NRS or CSS) were attenuated.Conclusions The RCQ demonstrated strong cross-sectional concordance with the LCQ across heterogeneous respiratory conditions. Its brevity and consistent performance support its suitability in routine clinical practice and large-scale or longitudinal research settings. Further studies are warranted to evaluate its responsiveness and longitudinal performance.

BACKGROUND AND OBJECTIVE:Ambient air pollution is known to exacerbate respiratory illnesses. However, its impact on COVID-19 outcomes remains underexplored. We investigated the association between ambient air pollution and outcomes in patients with moderate to severe COVID-19. METHODS:We analysed 1867 hospitalized patients from a multicentre Korean cohort. Individual-level exposure to five air pollutants (SO2, CO, NO2, PM10 and PM2.5) was assessed over short-term (3-day) and long-term (3-year) periods. The risks of acute respiratory distress syndrome (ARDS) and 30-day mortality were evaluated using models adjusted for clinical and meteorological factors. Pollutant exposure was analysed both as quartiles and continuous variables to estimate effects per unit increase. RESULTS:Short-term CO exposure was associated with increased ARDS incidence (per 0.1 ppm increase OR 1.18) and 30-day mortality (HR 1.15). Long-term NO2 exposure was associated with higher ARDS risk (per 1 ppb OR 1.11). Long-term PM10 exposure was also associated with ARDS incidence (per 10 μg/m3 OR 2.24). For mortality, short-term NO2 (per 1 ppb HR 1.02) and PM2.5 (per 10 μg/m3 HR 1.14) exposure were additionally associated with increased risk. These associations were consistent in quartile-based analyses. CONCLUSION:Both short- and long-term exposure to ambient air pollution were associated with worse COVID-19 outcomes, including ARDS and mortality. CO, often overlooked in pollution surveillance, showed the most consistent impact. These findings highlight the importance of air quality in pandemic preparedness and public health policy.

Background: The Health Insurance Review and Assessment Service (HIRA) in South Korea assesses and grades primary and secondary healthcare institutions according to their management of chronic obstructive pulmonary disease (COPD). This study examined whether changes in institutional quality assessment grades were associated with variations in the concurrent risk of acute COPD exacerbations. Methods: Using national HIRA claims data, we identified 36,218 patients with COPD treated at 873 non-tertiary medical institutions between May 2016 and April 2018. Institutions were stratified into three groups based on their grade trajectories from the 3rd (May 2016-April 2017) to the 4th (May 2017-April 2018) assessment periods: the 158 improved-grade (n=5,118), 526 maintained-grade (n=25,286), and 189 declined-grade (n=5,814) institution groups. We compared the incidence and severity of exacerbations among these groups during the 4th assessment period. Incidence rate ratios (IRRs) for exacerbations were estimated using multi-variable negative binomial regression models to adjust for potential confounders. Results: At baseline, improved-grade institutions exhibited significantly higher rates of pulmonary function testing (56.3% vs. 41.9%) and greater prescription of long-acting muscarinic antagonists (29.0% vs. 14.6%) compared with declined-grade institutions (p<0.001). During the 1-year outcome period (May 2017-April 2018), the incidence of moderate-to-severe COPD exacerbations was considerably higher in the declined-grade group (29.2%) than in the improved-grade group (26.1%) (p=0.008). In the negative binomial regression analyses using the maintained-grade group as the reference category, patients treated at improved-grade institutions had a significantly lower risk of exacerbations (adjusted IRR 0.864, 95% CI 0.795-0.939, p<0.001). Conclusion: This analysis of nationwide real-world claims data demonstrated that institutional improvement in COPD quality assessment grades was associated with a reduced concurrent risk of acute exacerbations in both primary and secondary care settings. These findings indicate that institutional indicators of guideline-aligned COPD care may correspond to clinically meaningful differences in patient-level outcomes.

Background:The distance-saturation product (DSP), calculated by multiplying 6-min walk distance (6MWD) by lowest oxygen saturation, is a composite physiological marker of exercise capacity and gas exchange impairment. Although DSP has shown prognostic potential in Western COPD cohorts, its utility and optimal threshold in Asian populations remain unestablished. This study evaluated whether DSP <290 m·% predicts exacerbations and mortality in COPD, compared with the BODE index. Methods:We analysed 1995 patients with valid 6MWD data from the Korean COPD Subgroup Study, a nationwide prospective cohort. DSP was dichotomised at 290 m·% based on restricted cubic spline analyses. Primary outcomes were 3-year acute exacerbations (AEs) and all-cause mortality. Associations were evaluated using multivariable logistic, negative binomial and Cox regression models, with the BODE index as comparator. Results:Patients with DSP <290 m·% had more severe symptoms, worse airflow limitation and more frequent prior-year AEs. Low DSP was independently associated with more frequent severe (adjusted incidence rate ratios (aIRRs) 2.27-2.54) and moderate (aIRRs 1.42-1.52) exacerbations, with significantly increased moderate AE risk observed only in year 1 (aOR 1.60; 95% CI 1.05-2.45). Patients with low DSP also had higher 3-year mortality (9.2% versus 2.6%, p<0.001), with a significantly increased risk of death (adjusted hazard ratio 2.74; 95% CI 1.68-4.45). DSP-based models demonstrated superior discrimination for 3-year mortality (area under the curve (AUC) 0.673) compared to the BODE index (AUC 0.636). Conclusions:DSP is a simple, scalable prognostic marker in COPD patients. A threshold of 290 m·% identifies patients at higher risk of exacerbations and mortality.

Chronic obstructive pulmonary disease (COPD) is a heterogeneous condition with multiple etiologies. We evaluated whether clinical characteristics differ according to COPD etiology. Patients with infection as the sole etiology were classified as the infection-related group (COPD-I, Group I), whereas those with any smoking-related etiology were assigned to the smoking-related group (COPD-C, Group C). Of 873 patients included, 41 were classified as Group I and 832 as Group C. A significantly higher proportion of patients in Group I had a blood eosinophil count < 100 cells/µL compared to Group C (44.4

Purpose:Young chronic obstructive pulmonary disease (COPD), distinct from COPD in older individuals, often remains underdiagnosed despite its potential for early interventions. This study aimed to identify the characteristics of young COPD patients and the patterns of lung function trajectory. Patients and Methods:This study was based on a large community-based cohort database in Korea. Young COPD was defined as COPD diagnosed in patients aged ≤ 50 years. We analyzed the clinical characteristics and lung function changes over 12 years, comparing young and old COPD patients. Results:Among the 9,577 patients enrolled in this study, 815 (8.5%) were diagnosed with COPD. The young COPD group had a higher proportion of females, never-smokers and a higher body mass index (BMI), compared to the older COPD group. The prevalence of young COPD increased from 117 (3.64%) to 334 (6.88%) according to the lower limit of normal (LLN) criteria. Analysis of lung function over 12 years revealed that the rate of decline in FEV1 (L), FEF25-75% (L), and FEV1/FVC ratio was slower in young COPD than in old COPD. Multivariate Cox analysis identified female sex, higher FEV1 (%), and young COPD as independent predictive factors for time-to-first normalization of airflow obstruction. Old COPD and low FEV1 (%) were identified as independent risk factors for time-to-first dyspnea. Conclusion:Young COPD is characterized by a higher proportion of females, non-smokers, and elevated BMI compared to old COPD. It has potential for lung function recovery and serves as an independent prognostic factor for the normalization of airflow obstruction.

BACKGROUND:Most clinical trials evaluating inhaler therapy in COPD have been conducted predominantly in smoking populations, and prognostic factors and therapeutic outcomes in COPD without any history of smoking were not well investigated. Therefore, this study was conducted to investigate the effect of inhaler prescription and comorbidities on the prognosis of COPD in never-smokers. METHODS:A retrospective observational study was undertaken using data from the Korean National Health Insurance Service-National Sample Cohort (NHIS-NSC) Survival analyses were performed according to inhaler prescriptions and comorbidities from index date to December 31, 2019. RESULTS:Among 2432 eligible patients, 382 (15.7%) received long-acting muscarinic antagonist(LAMA)/long-acting β2-agonist(LABA) therapy, 1780 (73.2%) received inhaled corticosteroid(ICS)/LABA, 187 (7.7%) received LAMA monotherapy, and 83 (3.4%) received LABA monotherapy. In multivariate Cox regression analysis, compared with the LAMA/LABA group, the ICS/LABA group had significantly higher all-cause (HR 1.65; 95% CI 1.22-2.24) and respiratory mortality (HR 1.72; 95% CI 1.07-2.77). Coexisting heart failure, frequent hospitalizations (≥2 times/year vs. none), and emergency room visits along with older age, male sex, and lower body mass index (BMI) were also independently associated with higher respiratory and all-cause mortality (p < 0.05). CONCLUSION:Our data in the cohort of non-smoking COPD suggest that LAMA/LABA therapy was associated with better survival rate compared with ICS/LABA therapy. Moreover, comorbid heart failure, frequent hospitalizations, emergency room visits, older age, male sex, and lower BMI were also independently linked to higher risks of respiratory and all-cause mortality.

BACKGROUND:Cough hypersensitivity is increasingly recognized as a key mechanism underlying chronic cough across diverse etiologies. The Cough Hypersensitivity Questionnaire (CHQ) was developed to systematically assess characteristic triggers and abnormal sensory perceptions; however, its structural and clinical relevance across respiratory diseases remains unclear. METHODS:We prospectively enrolled 300 adults with chronic cough from multiple respiratory centers. Participants completed four cough-related questionnaires: the Numeric Rating Scale (NRS), Leicester Cough Questionnaire (LCQ), Cough Assessment Test (COAT), and CHQ. Spearman correlation and network analyses were used to evaluate associations between CHQ items and other cough-related measures, including subgroup analyses by disease etiology. RESULTS:The CHQ demonstrated variable associations with conventional instruments and differing patterns across respiratory diseases. Triggers such as perfume and smoke correlated with LCQ hypersensitivity items, while the sensation item "urge to cough" exhibited broad correlations across physical, psychological, and social domains. Socially mediated triggers (e.g., talking) aligned with LCQ social interference items. In contrast, items such as hot air, dampness, laughter, and eating/drinking had minimal external associations. Internal CHQ correlations were sparse, and no significant associations were observed between CHQ and NRS, indicating a dissociation between hypersensitivity features and perceived severity. Disease-specific analyses suggested differing patterns, with broader associations observed in asthma and bronchiectasis compared with chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis. CONCLUSION:The CHQ captures distinct and heterogeneous dimensions of cough hypersensitivity that are not adequately reflected by conventional cough measures, suggesting its potential utility for characterizing clinically relevant multidimensional aspects of chronic cough.

BACKGROUND:Chronic obstructive pulmonary disease (COPD) and cardiovascular disease (CVD) frequently coexist and share common risk factors. However, the mortality burden associated with their co-occurrence has not been fully characterized at the population level, particularly with respect to cause-specific and absolute risks. METHODS:We conducted a population-based cohort study using data from UK Biobank. Participants were classified into four groups according to baseline COPD and CVD status. The primary outcome was all-cause mortality, and secondary outcomes included respiratory, cardiovascular, and lung cancer mortality. Multivariable Cox proportional-hazards models and competing-risk analyses were used to estimate adjusted hazard ratios (HRs). Absolute risks, risk differences, and numbers needed to harm (NNH) were calculated to quantify excess mortality burden. RESULTS:Among 293,948 participants followed for a median of 12.9 years, 3.9% had coexisting COPD and CVD at baseline. Compared to participants without either condition, those with both had a markedly increased risk of all-cause mortality (adjusted HR, 2.207 [95% confidence interval, 2.113-2.305]). Risks of respiratory-specific and cardiovascular-specific mortality were also substantially elevated. Although the COPD/CVD interaction was less than multiplicative on the HR scale, the absolute mortality burden was greatest among participants with both conditions. At 10 years, the excess absolute risk of all-cause mortality associated with coexisting COPD and CVD was 13.9 percentage points, corresponding to an NNH of 7.2. CONCLUSION:Coexisting COPD and CVD defines a distinct high-risk phenotype with a significantly increased absolute burden of all-cause and cause-specific mortality, underscoring the need for integrated cardiopulmonary risk management.

With increasing evidence of meaningful clinical benefit in patients with advanced emphysema, bronchoscopic lung volume reduction (BLVR) using endobronchial valves (EBVs) was included in the Global Initiative for Chronic Obstructive Lung Disease report, as well as US Food and Drug Administration approval. However, bilateral BLVR using an EBV has been rarely reported. We report a case of successful and safe bilateral BLVR with staged EBV insertion. A 65-year-old male was diagnosed with chronic obstructive pulmonary disease 5 years prior and has severe heterogeneous emphysema mainly situated in the right upper lobe and left lower lobe (LLL) with giant bullae in the right middle lobe. First, we successfully inserted an EBV into the right middle bronchus, and the bullae decreased dramatically in size. After 6 months of initial valve implantation, we inserted five additional valves into the left lower bronchi of the patient. About 3 years after the secondary EBV insertion, this patient experienced hemoptysis and aggravation of dyspnea. In bronchoscopy, EBV inserted into LB6 was displaced with the formation of granulation tissue, so the EBV was removed. Later, LB6 was fully obstructed by granulation tissue. Then, we inserted an additional EBV into the LLL basal segmental bronchus, and complete atelectasis of the LLL occurred. The patient's pulmonary function, symptoms, and quality of life were further improved. BLVR can serve as a good alternative treatment for appropriately selected patients, and the procedure can be repeated on the contralateral side of the lung. It is important to recognize granulation tissue formation and deal with them appropriately.

BACKGROUND:Socioeconomic status (SES) significantly influences the incidence and severity of chronic obstructive pulmonary disease. This study investigated the impact of SES on incidence of airflow obstruction and lung function decline within a general population cohort in Republic of Korea (South Korea). METHODS:We utilized data from the Korean Genome and Epidemiology Study Ansan-Ansung Cohort, collected between 2001 and 2014. A total of 10,030 participants were included in the longitudinal analysis. Socioeconomic status was classified using four key indicators: area of residence (urban, n = 5,012; rural, n = 5,018), marital status (single, n = 974; married, n = 8,987), education level (elementary school, n = 3,355; middle or high school, n = 5,287; college or above, n = 1,305), and income (< $1,460, n = 6,413; $1,460-2,920, n = 2,705; > $2,920, n = 729), among participants with available data. RESULTS:Over a 12-year follow-up period, individuals living in rural areas experienced a more rapid decline in both mean forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC) compared to those in urban areas (P < 0.001). Participants with the lowest levels of education and income experienced significantly faster declines in both FVC and FEV₁ (all P < 0.001, except for medium vs. high income). The risk of developing airflow obstruction was significantly higher for participants from rural areas, with lower education levels, and lower income. CONCLUSION:This study demonstrated a significant association between lower SES and incidence of airflow obstruction and progression in Korea. Lower SES, characterized by rural residence, lower educational status, and lower income, was associated with poorer baseline health, higher comorbidity rates, and more rapid lung function decline over a 12-year period.

Background:Persistent airflow limitation (PAL) is an increasingly recognized asthma phenotype, but its prevalence, determinants, and prognostic significance in real-world settings remain unclear. This study evaluated the clinical characteristics and long-term outcomes associated with PAL and its severity in asthma. Methods:Multicenter analysis of combined retrospective and prospective cohorts in South Korea. PAL was defined as post-bronchodilator FEV1/FVC <0.70; severity was graded by STaging of Airflow obstruction by Ratio classification (STAR stage). Outcomes included subsequent exacerbations and longitudinal lung function change. Results:Among 849 patients with asthma, 640 (75.4%) had PAL. PAL was associated with older age, male sex, lower body mass index, higher smoking intensity, lower FEV1, history of tuberculosis, and less frequent allergic rhinitis. Optimal predictors of PAL were FEV1 ≤83.7% predicted, age ≥63.5 years, and smoking intensity ≥9.5 pack-years. During follow-up, severe exacerbations occurred more frequently in the PAL group (13.0% vs 5.7%) with a 1.8-fold higher incidence (IRR 1.77, 95% CI 1.13-2.79). Risk increased with PAL severity, particularly at STAR stage 4 vs stage 0 (aHR 3.32, 95% CI 1.60-6.89). Longitudinally, annual FEV1 decline was slower in PAL than in non-PAL (-28.1 vs -42.5 mL/year, P = 0.028), but within PAL, STAR stage 4 showed relatively faster declines in both FEV1 and FVC. Conclusion:PAL and its severity independently predict the risk of severe exacerbations and progressive lung function decline in asthma, underscoring PAL as a key marker of disease progression and a potential target for early intervention.

BACKGROUND:The Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2026 strategy lowered the threshold for defining high-risk COPD by classifying patients with a single moderate exacerbation as high risk (group E). Evidence supporting the prognostic significance of this change remains limited. RESEARCH QUESTION:Does 1 moderate exacerbation identify patients at increased risk of future exacerbations and long-term mortality, and does the GOLD 2026 exacerbation-based risk definition improve prognostic performance compared with GOLD 2025? STUDY DESIGN AND METHODS:We analyzed data from the Korean COPD Subgroup Study (KOCOSS), a prospective multicenter COPD cohort. Patients were classified by exacerbation history during the first year as no exacerbation, 1 moderate exacerbation, or ≥ 2 moderate or ≥ 1 severe exacerbations. Future exacerbations during the second year were evaluated using negative binomial regression. Twelve-year all-cause and respiratory mortality were assessed using Cox proportional hazards models. The prognostic performance of GOLD 2025 and GOLD 2026 exacerbation-based risk definitions was compared using time-dependent area under the curve analysis. RESULTS:Among 1,551 patients, 241 (15.5%) experienced 1 moderate exacerbation, and 392 (25.3%) experienced frequent or severe exacerbations. Compared with no exacerbations, 1 moderate exacerbation was associated with higher risks of future moderate-to-severe exacerbations (adjusted incidence rate ratio, 2.42; 95% CI, 1.85-3.17) and severe exacerbations (adjusted incidence rate ratio, 2.21; 95% CI, 1.27-3.85). Over long-term follow-up of up to 12 years, 1 moderate exacerbation was independently associated with increased all-cause mortality (adjusted hazard ratio, 1.49; 95% CI, 1.02-2.15) and respiratory mortality (adjusted hazard ratio, 3.21; 95% CI, 1.76-5.88). The GOLD 2026 definition showed better 10-year discrimination for all-cause mortality than the GOLD 2025 definition (area under the receiver operating characteristic curve, 0.760 vs 0.734; Δ area under the receiver operating characteristic curve, 0.025; 95% CI, 0.004-0.046). INTERPRETATION:Our results show that a single moderate exacerbation identifies patients at increased risk of future exacerbations and mortality, supporting their classification as high risk under GOLD 2026.