Background: Asthma remission has recently emerged as an aspirational treatment goal, yet its definition remains inconsistent across studies and expert groups. The absence of a standardized framework hampers its application in clinical practice and research, particularly in Korea where biologics use is rapidly increasing. This study aimed to establish a consensus definition of clinical remission in severe asthma among Korean experts. Methods: A two-round modified Delphi survey, followed by a focused third round, was conducted among 28 board-certified pulmonologists from the Korean Academy of Tuberculosis and Respiratory Diseases (KATRD). The questionnaire consisted of six domains and 27 items. Responses were analyzed using agreement rates, interquartile ranges, and content validity ratios to determine consensus levels. Results: Consensus was reached on defining clinical remission as a composite of no exacerbations, no systemic corticosteroid use, sustained symptom control (Asthma Control Test ≥20 on at least three occasions over 12 months), and stabilization and optimization of pulmonary function while on maintenance treatment. Experts agreed that pulmonary function should be assessed based on clinical judgment rather than absolute thresholds. Complete remission was additionally defined as fulfilling all clinical remission criteria with normalization of type 2 inflammation (blood eosinophils <300/μL and fractional exhaled nitric oxide <25 ppb). Conclusion This Delphi consensus provides a regionally relevant and pragmatic framework for defining remission in severe asthma. These statements may help guide clinical practice, inform guideline development, and support future research on remission as a treatment goal.

Background: Bronchiectasis has a complex and heterogeneous pathogenesis, with various etiologies, the majority being idiopathic. This study aimed to examine the characteristics of patients with idiopathic bronchiectasis in comparison to those with post-infectious bronchiectasis. Methods: We analyzed data from patients with idiopathic and post-infectious bronchiectasis (including post-tuberculosis) from the Korean Multicenter Bronchiectasis Audit and Research Collaboration (KMBARC) registry, a prospective cohort study. Results: Among the 866 patients enrolled in the study, 346 (40.0%) were classified as having idiopathic bronchiectasis, while 363 (41.9%) had post-infectious bronchiectasis. The idiopathic group demonstrated a shorter disease duration, a higher body mass index (BMI), a lower prevalence of chronic obstructive pulmonary disease (COPD), a higher prevalence of rhinosinusitis, a predominance of lower lobe distribution, less frequent use of regular respiratory treatments, better pulmonary function, and a statistically lower bronchiectasis severity index compared to the post-infectious group. A multivariable logistic regression analysis was conducted, considering factors such as gender, age, BMI, history of asthma, COPD, rhinosinusitis, rheumatoid arthritis, gastroesophageal reflux disease, and smoking status. A higher BMI (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.04 to 1.15) and a history of rhinosinusitis (OR, 3.10; 95% CI, 1.57 to 6.14) were associated with idiopathic bronchiectasis. In contrast, a history of COPD was linked to post-infectious bronchiectasis (OR, 0.57; 95% CI, 0.41 to 0.80). Conclusion Patients with idiopathic bronchiectasis are characterized by a higher BMI and a history of rhinosinusitis compared to those with post-infectious bronchiectasis. These findings may provide exploratory insights into underlying systemic or non-pulmonary factors. Further research is necessary to clarify the clinical significance of these associations.

Background: Patients with chronic obstructive pulmonary disease (COPD) expressing eosinophilia experience slightly fewer episodes of community-acquired pneumonia (CAP), than those without eosinophilia. However, the severity and burden of hospitalized pneumonia patients with COPD involving eosinophilia have not been assessed. Methods: We evaluated the differences in clinical characteristics between patients with CAP and COPD with or without eosinophilia by a post hoc analysis of a prospective, multi-center, cohort study data. Results: Of 349 CAP patients with COPD, 45 (12.9%) had eosinophilia (blood eosinophil ≥300 cells/μL). Patients with eosinophilia had a lower sputum culture percentile (8.1% vs. 23.4%, p<0.05), a lower percentile of neutrophils (70.3% vs. 80.2%, p<0.05), reduced C-reactive protein levels (30.6 mg/L vs. 86.6 mg/L, p<0.05), and a lower pneumonia severity index score (82.5 vs. 90.0, p<0.05), than those without eosinophilia. The duration of antibiotic treatment (8.0 days vs. 10.0 days, p<0.05) and hospitalization (7.0 days vs. 9.0 days, p<0.05) were shorter in eosinophilic patients. The cost of medical care per day (256.4 US$ vs. 291.0 US$, p<0.05), cost for the medication (276.4 US$ vs. 349.9 US$, p<0.05), and cost for examination (685.5 US$ vs. 958.1 US$, p<0.05) were lower in patients with eosinophilia than those without eosinophilia. Conclusion Eosinophilia serves as a favorable marker for the severity of pneumonia, health-care consumption, and cost of medical care in patients with CAP and COPD.

Objectives: This study was conducted to evaluate burnout and its associated factors among coronavirus disease 2019 (COVID-19) frontline healthcare workers. Methods: We analyzed the nationwide burnout evaluation scale data collected from 774 COVID-19 frontline healthcare workers in South Korea from July 1 to 14, 2021. Along with demographic variables and work-related information, the Maslach Burnout Inventory–General Survey and the list of stress factors were used to assess burnout and its associated stressors. Results: The study participants were predominantly female (86.2%) and the majority were nurses (78.8%). Among them, 53.0% felt emotionally exhausted, 34.5% were cynical, and 45.5% experienced decreased professional efficacy. The most common stressors were “insufficient rewards” (85.0%) and “excessive workload” (72.5%). Factors such as excessive workload, interpersonal relationships at work, and stress from insufficient rewards were correlated with higher levels of exhaustion and increased cynicism. Insufficient rewards and stress about family infection were associated with increased professional efficacy. Conclusion Stress related to the work environment, rather than that from potential infection, was associated with exhaustion and cynicism in the COVID-19 frontline healthcare workers.

Background/Aims: The overall incidence of pneumococcal pneumonia is declining. However, the change in the pathogenic distribution of community-acquired pneumonia (CAP) in chronic obstructive pulmonary disease (COPD) patients and the serotype specificity of Streptococcus pneumoniae have not been evaluated in the post-era of pneumococcal vaccination in Korea. Methods: We conducted a prospective, multi-center, cohort study from seven University-affiliated hospitals. The primary objective was the identification of serotype-specific prevalence of pneumococcal pneumonia in COPD patients hospitalized for CAP. For the purpose, we conducted serotype-specific urine antigen detection (SS-UAD) assays for S. pneumoniae. The secondary objectives were other clinical characteristics of pneumonia including vaccination status. Results: The total number of participants was 349. Most of them were male (95.1%) with old ages (75.55 ± 8.59 y). The positive rate for S. pneumoniae was 9.2% with SS-UAD assay and the common serotypes were 22F, 6A, and 6B. In the sputum, Pseudomonas aeruginosa (5.0%) and Haemophilus influenzae (4.0%) were common pathogens. The vaccination rate was 78.8%, 53.0%, and 25.8% for influenza, pneumococcal polysaccharide vaccine 23 (PPV 23), and pneumococcal protein- conjugated vaccine 13 (PCV 13), respectively. Thirteen patients died during hospitalization (mortality rate; 3.7%). There was no difference in the respective rate of influenza vaccination (79.2% vs. 69.2%, p = 0.288) and PCV 13 vaccination (25.6% vs. 30.8%, p = 0.443) between survivors and the deceased. Conclusions Serotypes 22F, 6A, and 6B, which are covered either by PPV 23 or by PCV 13, are still common pneumococcal serotypes in COPD pneumonia in the post-vaccination era in Korea.

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

Background: Drug-induced parkinsonism (DIP) is common, but diagnosis is challenging.Although dopamine transporter imaging is useful, the cost and inconvenience are problematic, and an easily accessible screening technique is needed. We aimed to determine whether optical coherence tomography (OCT) findings could differentiate DIP from Parkinson’s disease (PD). Methods: We investigated 97 de novo PD patients and 27 DIP patients using OCT and [ 18 F] N-(3-fluoropropyl)-2b-carbon ethoxy-3b-(4-iodophenyl) nortropane (FP-CIT) positron emission tomography. We compared peripapillary retinal nerve fiber layer thickness (pRNFLT) and macular retinal thickness (mRT) between PD and DIP patients as well as interocular differences in the pRNFLT and the mRT. Asymmetric index (%) for retinal thickness (AIRT) was calculated to measure the interocular differences between pRNFLT and mRT. The correlation between AIRT and total striatal specificon-specific binding ratio asymmetry index (SNBRAI) was investigated in PD and DIP patients. Results: No significant differences in pRNFLT and mRT values were observed between PD and DIP patients (all Pvalues > 0.090). The mean SNBRAI was significantly higher in PD than in DIP (P = 0.008) patients; however, AIRT did not differ between PD and DIP patients in pRNFLT and mRT (all P values > 0.100). SNBRAI did not correlate with AIRT of pRNFL or mRT in PD and DIP patients (all P values > 0.060). Conclusion Our study showed no benefit of retinal thickness and interocular asymmetry measurements using OCT for distinguishing PD from DIP in the early stages. Additional investigations are needed for confirmation.

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 VO 2 max using exercise capacity equations in Korean subjects. Methods: This retrospective study enrolled 383 patients who underwent cardiopulmonary exercise test (CPET) with incremental maximal cycle ergometer test at Asan Medical Center from January 2020 to May 2021. Stage 1 and 2 lung cancer patients with normal lung function and healthy persons of 50 subjects who had maximal CPET were analyzed. Results: The subjects were aged 65 ± 13 years and predominantly male (74%). CPET results were as follows: absolute VO2 max, 1.2 ± 0.3 L/min; body weight referenced VO2 max, 20 ± 3.9 mL/kg/min; peak work rate, 94 ± 24 watts; peak heart rate, 142 ± 21 bpm; peak O 2 pulse, 10 ± 3 mL/beat; minute ventilation, 59 ± 14 L/min; peak respiratory rate, 34 ± 6 breaths per minute; and peak breathing reserve, 41 ± 18%. There was significant discordance between the measured and predicted absolute VO2 max using the Jones, Hansen, and Wasserman prediction equations developed for Caucasian population (P < 0.001). Agreement using Bland-Altman test between true and predicted absolute VO2 max was the best in Chinese equation (−0.03, 2SD = 0.55) compared to Jones (0.42, 2SD = 1.07), Hansen (0.44, 2SD = 0.86), and Wasserman (0.42, 2SD = 0.86) equations. Conclusion The reference value and prediction equation from studies including primarily Caucasians may not be appropriate for Koreans. Since the mean difference is the lowest in Chinese equation, the Chinese equation might be used for the Korean adult population.