Background: Programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) inhibitors are effective treatments for non-small cell lung cancer (NSCLC), but their use can lead to severe pneumonitis. This study aims to evaluate the utility of Krebs von den Lungen-6 (KL-6) for predicting and diagnosing PD-1/PD-L1 inhibitor-related pneumonitis in NSCLC patients. Methods: We conducted a prospective observational study at a university-affiliated tertiary hospital in Korea from February 2022 to June 2023. Baseline KL-6 levels were measured immediately before initiating PD-1/PD-L1 inhibitor therapy. In patients who developed pneumonitis, KL-6 levels were monitored every 1–2 weeks from the onset of pneumonitis. For patients without pneumonitis, KL-6 levels were measured every 6 weeks. We compared clinical characteristics and serial KL-6 levels between the pneumonitis and non-pneumonitis groups. Results: Eighteen patients were enrolled, with 11 developing pneumonitis. Baseline KL-6 levels did not significantly differ between the two groups (261 U/mL in the pneumonitis group vs. 373 U/mL in the non-pneumonitis group, p=0.375). In the pneumonitis group, KL-6 levels generally showed an upward trend, with a median of 412 U/mL at pneumonitis onset. Conversely, KL-6 levels in the non-pneumonitis group showed no clear overall change. Conclusion In this pilot study, baseline KL-6 was not clearly linked to PD-1/PD-L1 inhibitor-related pneumonitis in NSCLC patients. However, increases in KL-6 levels post-baseline were more frequently observed in patients who developed pneumonitis, including cases of all-cause pneumonitis.

Mechanical power (MP) has been reported to be associated with clinical outcomes. Because the original MP equation is derived from paralyzed patients under volume-controlled ventilation, its application in practice could be limited in patients receiving pressure-controlled ventilation (PCV). Recently, a simplified equation for patients under PCV was developed. We investigated the association between MP and intensive care unit (ICU) mortality. Methods: We conducted a retrospective analysis of Korean data from the Fourth International Study of Mechanical Ventilation. We extracted data of patients under PCV on day 1 and calculated MP using the following simplified equation: MPPCV = 0.098 ∙ respiratory rate ∙ tidal volume ∙ (ΔPinsp + positive end-expiratory pressure), where ΔPinsp is the change in airway pressure during inspiration. Patients were divided into survivors and non-survivors and then compared. Multivariable logistic regression was performed to determine association between MPPCV and ICU mortality. The interaction of MPPCV and use of neuromuscular blocking agent (NMBA) was also analyzed. Results: A total of 125 patients was eligible for final analysis, of whom 38 died in the ICU. MPPCV was higher in non-survivors (17.6 vs. 26.3 J/min, P<0.001). In logistic regression analysis, only MPPCV was significantly associated with ICU mortality (odds ratio, 1.090; 95% confidence interval, 1.029–1.155; P=0.003). There was no significant effect of the interaction between MPPCV and use of NMBA on ICU mortality (P=0.579). Conclusions: MPPCV is associated with ICU mortality in patients mechanically ventilated with PCV mode, regardless of NMBA use.

Mechanical power (MP) has been reported to be associated with clinical outcomes. Because the original MP equation is derived from paralyzed patients under volume-controlled ventilation, its application in practice could be limited in patients receiving pressure-controlled ventilation (PCV). Recently, a simplified equation for patients under PCV was developed. We investigated the association between MP and intensive care unit (ICU) mortality. Methods: We conducted a retrospective analysis of Korean data from the Fourth International Study of Mechanical Ventilation. We extracted data of patients under PCV on day 1 and calculated MP using the following simplified equation: MPPCV = 0.098 ∙ respiratory rate ∙ tidal volume ∙ (ΔPinsp + positive end-expiratory pressure), where ΔPinsp is the change in airway pressure during inspiration. Patients were divided into survivors and non-survivors and then compared. Multivariable logistic regression was performed to determine association between MPPCV and ICU mortality. The interaction of MPPCV and use of neuromuscular blocking agent (NMBA) was also analyzed. Results: A total of 125 patients was eligible for final analysis, of whom 38 died in the ICU. MPPCV was higher in non-survivors (17.6 vs. 26.3 J/min, P<0.001). In logistic regression analysis, only MPPCV was significantly associated with ICU mortality (odds ratio, 1.090; 95% confidence interval, 1.029–1.155; P=0.003). There was no significant effect of the interaction between MPPCV and use of NMBA on ICU mortality (P=0.579). Conclusions: MPPCV is associated with ICU mortality in patients mechanically ventilated with PCV mode, regardless of NMBA use.

Mechanical power (MP) has been reported to be associated with clinical outcomes. Because the original MP equation is derived from paralyzed patients under volume-controlled ventilation, its application in practice could be limited in patients receiving pressure-controlled ventilation (PCV). Recently, a simplified equation for patients under PCV was developed. We investigated the association between MP and intensive care unit (ICU) mortality. Methods: We conducted a retrospective analysis of Korean data from the Fourth International Study of Mechanical Ventilation. We extracted data of patients under PCV on day 1 and calculated MP using the following simplified equation: MPPCV = 0.098 ∙ respiratory rate ∙ tidal volume ∙ (ΔPinsp + positive end-expiratory pressure), where ΔPinsp is the change in airway pressure during inspiration. Patients were divided into survivors and non-survivors and then compared. Multivariable logistic regression was performed to determine association between MPPCV and ICU mortality. The interaction of MPPCV and use of neuromuscular blocking agent (NMBA) was also analyzed. Results: A total of 125 patients was eligible for final analysis, of whom 38 died in the ICU. MPPCV was higher in non-survivors (17.6 vs. 26.3 J/min, P<0.001). In logistic regression analysis, only MPPCV was significantly associated with ICU mortality (odds ratio, 1.090; 95% confidence interval, 1.029–1.155; P=0.003). There was no significant effect of the interaction between MPPCV and use of NMBA on ICU mortality (P=0.579). Conclusions: MPPCV is associated with ICU mortality in patients mechanically ventilated with PCV mode, regardless of NMBA use.

Mechanical power (MP) has been reported to be associated with clinical outcomes. Because the original MP equation is derived from paralyzed patients under volume-controlled ventilation, its application in practice could be limited in patients receiving pressure-controlled ventilation (PCV). Recently, a simplified equation for patients under PCV was developed. We investigated the association between MP and intensive care unit (ICU) mortality. Methods: We conducted a retrospective analysis of Korean data from the Fourth International Study of Mechanical Ventilation. We extracted data of patients under PCV on day 1 and calculated MP using the following simplified equation: MPPCV = 0.098 ∙ respiratory rate ∙ tidal volume ∙ (ΔPinsp + positive end-expiratory pressure), where ΔPinsp is the change in airway pressure during inspiration. Patients were divided into survivors and non-survivors and then compared. Multivariable logistic regression was performed to determine association between MPPCV and ICU mortality. The interaction of MPPCV and use of neuromuscular blocking agent (NMBA) was also analyzed. Results: A total of 125 patients was eligible for final analysis, of whom 38 died in the ICU. MPPCV was higher in non-survivors (17.6 vs. 26.3 J/min, P<0.001). In logistic regression analysis, only MPPCV was significantly associated with ICU mortality (odds ratio, 1.090; 95% confidence interval, 1.029–1.155; P=0.003). There was no significant effect of the interaction between MPPCV and use of NMBA on ICU mortality (P=0.579). Conclusions: MPPCV is associated with ICU mortality in patients mechanically ventilated with PCV mode, regardless of NMBA use.

Background: and Purpose The association between physical activity and dementia has been shown in various observational studies. We aimed to determine the risk of dementia in the elderly with lower-body fractures. Methods: We reconstructed a population-based matched cohort from the National Health Insurance Service—Senior Cohort data set that covers 511,953 recipients of medical insurance in South Korea. Results: Overall 53,776 subjects with lower-body fractures were identified during 2006–2012, and triplicate control groups were matched randomly by sex, age, and years from the index date for each subject with a fracture. There were 3,573 subjects (6.6%) with and 7,987 subjects (4.9%) without lower-body fractures who developed dementia from 2008 up to 2015. Lowerbody fractures were independently associated with a subsequent dementia diagnosis with a higher adjusted hazard ratio (aHR) (1.55, 95% confidence interval [CI]=1.49–1.62) compared with upper-body fractures (aHR=1.19, 95% CI=1.14–1.23). Conclusions These results support the protective role of physical activity against dementia and highlight the importance of promoting fracture prevention in the elderly.

Background: The prevalence of chronic obstructive pulmonary disease (COPD) increases with age, and aging is an important risk factor for COPD development. In the era of global aging, demographic information about the prevalence of and factors associated with COPD are important to establish COPD care plans. However, limited information is available in rapidly aging societies, including Korea. Methods: We conducted a cross-sectional observational study using Korea National Health and Nutrition Examination Survey data from 2015–2019. We included 15,613 participants and analyzed trends of and factors associated with COPD. Results: During the study period, the overall prevalence of COPD was 12.9%. Over five years, the yearly prevalence of COPD was fairly constant, ranging from 11.5% to 13.6%. Among individuals aged ≥ 70 years, nearly one-third met COPD diagnostic criteria. In the multivariable analysis, age 70 years or older was the most strong factor associated with COPD (adjusted odds ratio [aOR], 17.86; 95% confidence interval [CI], 14.16–22.52; compared with age 40–49), followed by asthma (aOR, 3.39; 95% CI, 2.44–4.71), male sex (aOR, 2.64; 95% CI, 2.18–3.19), and current smokers (aOR, 2.60; 95% CI, 2.08–3.25). Additionally, exsmokers, low income, decreased forced expiratory volume in 1 second %pred, and a history of pulmonary tuberculosis were associated with COPD. On the other hand, body mass index (BMI) ≥ 25 kg/m 2 (aOR, 0.62; 95% CI, 0.54–0.71; compared with BMI 18.5–24.9 kg/m 2 ) had an inverse association with COPD. Conclusion Recent trends in the prevalence of COPD in South Korea are relatively stable.Approximately one-third of participants aged 70 years and older had COPD. Aging was the most important factor associated with COPD.

Background/Aims: Patients with bronchiectasis often present with respiratory symptoms caused by chronic rhinosinusitis (CRS). However, studies on the prevalence of CRS and its relationship with bronchiectasis are limited. Methods: The baseline characteristics of patients with bronchiectasis recruited from the Korean Multicenter Bronchiectasis Audit and Research Collaboration were analyzed. CRS diagnosis was determined by a physician, on the basis of medical records, upper airway symptoms, and/or radiologic abnormalities. Questionnaires for quality of life, fatigue, and depression were administered when patients were stable for a minimum of 4 weeks after the bronchiectasis exacerbation. Results: The prevalence of CRS was 7.1% (66/931). Patients with CRS were significantly younger than those without CRS (60.5 ± 10.7 years vs. 64.6 ± 9.3 years, p = 0.001). Idiopathic bronchiectasis was more common in patients with CRS compared to those without CRS (53.0% vs. 36.0%, p = 0.006). Lung function, inflammatory markers, exacerbations, bronchiectasis severity, and scores for quality of life, fatigue, and depression did not differ between the two groups. In a logistic regression analysis, CRS was associated with age of bronchiectasis diagnosis (odds ratio [OR], 0.96; 95% confidence interval [CI], 0.94 to 0.99; p = 0.003) and idiopathic bronchiectasis (OR, 1.95; 95% CI, 1.12 to 3.34; p = 0.018). Conclusions The prevalence of CRS was relatively low. CRS was not associated with the severity or clinical outcomes of bronchiectasis. Early diagnosis and idiopathic etiology were associated with CRS. Our findings reflect the low recognition of CRS in the clinical practice of bronchiectasis and highlight the need for awareness of CRS by adopting objective diagnostic criteria.

Background/Aims: There are few studies describing contemporary status of mechanical ventilation in Korea. We investigated changes in management and outcome of mechanical ventilation in Korea. Methods: International, prospective observational cohort studies have been conducted every 6 years since 1998. Korean intensive care units (ICUs) participated in 2010 and 2016 cohorts. We compared 2016 and 2010 Korean data. Results: Two hundred and twenty-six patients from 18 ICUs and 275 patients from 12 ICUs enrolled in 2016 and 2010, respectively. In 2016 compared to 2010, use of non-invasive ventilation outside ICU increased (10.2% vs. 2.5%, p = 0.001). Pressure-control ventilation was the most common mode in both groups. Initial tidal volume (7.1 mL/kg vs. 7.4 mL/kg, p = 0.372) and positive end-expiratory pressure (6 cmH2O vs. 6 cmH2O, p = 0.141) were similar, but peak pressure (22 cmH2O vs. 24 cmH2O, p = 0.011) was lower in 2016. More patients received sedatives (70.7% vs. 57.0%, p = 0.002) and analgesics (86.5% vs. 51.1%, p < 0.001) in 2016. The awakening (48.4% vs. 31.0%, p = 0.002) was more frequently attempted in 2016. The accidental extubation rate decreased to one tenth of what it was in 2010 (1.1% vs. 10.2%, p < 0.001). The ICU mortality did not change (31.4% 35.6%, p = 0.343) but ICU length of stay showed a decreasing trend (9 days vs. 10 days, p = 0.054) in 2016. Conclusions There were temporal changes in care of patients on mechanical ventilation including better control of pain and agitation, and active attempt of awakening.

Background: Asthma–chronic obstructive pulmonary disease (COPD) overlap (ACO) is a condition characterized by the overlapping clinical features of asthma and COPD. To evaluate the appropriateness of different sets of ACO definition, we compared the clinical characteristics of the previously defined diagnostic criteria and the specialist opinion in this study. Methods: Patients enrolled in the KOrea COpd Subgroup Study (KOCOSS) were evaluated. Based on the questionnaire data, the patients were categorized into the ACO and non-ACO COPD groups according to the four sets of the diagnostic criteria. Results: In total 1,475 patients evaluated: 202 of 1,475 (13.6%), 32 of 1,475 (2.2%), 178 of 1,113 (16.0%), and 305 of 1,250 (24.4%) were categorized as ACO according to the modified Spanish Society of Pneumonology and Thoracic Surgery (SEPAR), American Thoracic Society (ATS) Roundtable, Global Initiative for Asthma (GINA)/Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria, and the specialists diagnosis, respectively. The ACO group defined according to the GINA/GOLD criteria showed significantly higher St. George's Respiratory Questionnaire and COPD Assessment Test scores than the non-ACO COPD group. When the modified SEPAR definition was applied, the ACO group showed a significantly larger decrease in the forced expiratory volume in 1 second (FEV1, %). The ACO group defined by the ATS Roundtable showed significantly larger decrease in the forced vital capacity values compared to the non-ACO COPD group (–18.9% vs. –2.2%, p=0.007 and –412 mL vs. –17 mL, p=0.036). The ACO group diagnosed by the specialists showed a significantly larger decrease in the FEV1 (%) compared to the non-ACO group (–5.4% vs. –0.2%, p=0.003). Conclusion In this study, the prevalence and clinical characteristics of ACO varied depending on the diagnostic criteria applied. With the criteria which are relatively easy to use, defining ACO by the specialists diagnosis may be more practical in clinical applications.