Background and objective PPFE is characterized by fibrosis in the pleura and subpleural lung parenchyma in the upper lobes, while other types of ILD, mainly UIP, can be observed in about half of the patients in their lower lobes. The aim of this study was to evaluate the clinical significance of the radiologically defined PPFE in patients with IPF. Methods Clinical data and chest CT images were retrospectively analysed in 445 patients with IPF (biopsy‐proven cases, n = 165). The radiological criteria of PPFE were defined as follows: (i) bilateral subpleural dense fibrosis with or without pleural thickening in the upper lobes, (ii) evidence of disease progression and (iii) no clinical evidence of identifiable aetiologies. Results The median follow‐up period was 43.0 months. The mean age of the patients was 66.4 years and 76.4% were male. PPFE was identified in 28 patients (6.3%). The PPFE group showed lower BMI and lung function (FVC and TLC) at baseline, more frequent pneumothorax and pneumomediastinum, higher decline rates in lung function and poorer prognosis during follow‐up than the no‐PPFE group. PPFE was an independent risk factor (HR = 2.953, 95% CI: 1.350–6.460, P = 0.007) for pneumothorax or pneumomediastinum, but not for mortality in patients with IPF. Conclusion Among patients with IPF, the PPFE group, when compared to the no‐PPFE group, showed lower BMI and lung function and showed more frequent complications and poorer survival during follow‐up.

Background Immune checkpoint inhibitors (ICIs) have become the standard of care for a variety of cancers, including non-small cell lung cancer (NSCLC). In this study, we investigated the frequency of pseudoprogression and hyperprogression in lung cancer patients treated with ICIs in the real world and aimed to discover a novel candidate marker to distinguish pseudoprogression from hyperprogression soon after ICI treatment. Methods This study included 74 patients with advanced NSCLC who were treated with PD-1/PD-L1 inhibitors at Chungnam National University Hospital (CNUH) between January 2018 and August 2020. Chest X-rays were examined on day 7 after the first ICI dose to identify changes in the primary mass, and the response was assessed by computed tomography (CT). We evaluated circulating regulatory T (Treg) cells using flow cytometry and correlated the findings with clinical outcomes. Results The incidence of pseudoprogression was 13.5%, and that of hyperprogression was 8.1%. On day 7 after initiation of treatment, the frequency of CD4+CD25+CD127loFoxP3+ Treg cells was significantly decreased compared with baseline (P = 0.038) in patients who experienced pseudoprogression and significantly increased compared with baseline (P = 0.024) in patients who experienced hyperprogression. In the responder group, the frequencies of CD4+CD25+CD127loFoxP3+ Treg cells and PD-1+CD4+CD25+CD127loFoxP3+ Treg cells were significantly decreased 7 days after commencement of treatment compared with baseline (P = 0.034 and P < 0.001, respectively). Conclusion Circulating Treg cells represent a promising potential dynamic biomarker to predict efficacy and differentiate atypical responses, including pseudoprogression and hyperprogression, after immunotherapy in patients with NSCLC.

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Background The ratio of oxygen saturation (ROX) index, defined as the ratio of oxygen saturation (SpO2)/fraction of inspired oxygen (FiO2) to respiratory rate, can help identify patients with hypoxemic respiratory failure at high risk for intubation following high-flow nasal cannula (HFNC) initiation; however, whether it is effective for predicting intubation in coronavirus disease 2019 (COVID-19) patients receiving HFNC remains unknown. Moreover, the SpO2/FiO2 ratio has been assessed as a prognostic marker for acute hypoxemic respiratory failure. This study aimed to determine the utility of the ROX index and the SpO2/FiO2 ratio as predictors of failure in COVID-19 patients who received HFNC. Methods This multicenter study was conducted in seven university-affiliated hospitals in Korea. Data of consecutive hospitalized patients diagnosed with COVID-19 between February 10, 2020 and February 28, 2021 were retrospectively reviewed. We calculated the ROX index and the SpO2/FiO2 ratio at 1 h, 4 h, and 12 h after HFNC initiation. The primary outcome was HFNC failure defined as the need for subsequent intubation despite HFNC application. The receiver operating characteristic curve analysis was used to evaluate discrimination of prediction models for HFNC failure. Results Of 1,565 hospitalized COVID-19 patients, 133 who received HFNC were analyzed. Among them, 63 patients (47.4%) were successfully weaned from HFNC, and 70 (52.6%) were intubated. Among patients with HFNC failure, 32 (45.7%) died. The SpO2/FiO2 ratio at 1 h after HFNC initiation was an important predictor of HFNC failure (AUC 0.762 [0.679–0.846]). The AUCs of SpO2/FiO2 ratio at 4 h and ROX indices at 1 h and 4 h were 0.733 (0.640–0.826), 0.697 (0.597–0.798), and 0.682 (0.583–0.781), respectively. Multivariable analysis showed that the patients aged ≥70 years are 3.4 times more likely to experience HFNC failure than those aged <70 years (HR 3.367 [1.358–8.349], p = 0.009). The SpO2/FiO2 ratio (HR 0.983 [0.972–0.994], p = 0.003) at 1 h was significantly associated with HFNC failure. Conclusions The SpO2/FiO2 ratio following HFNC initiation was an acceptable predictor of HFNC failure. The SpO2/FiO2 ratio may be a good prognostic marker for predicting intubation in COVID-9 patients receiving HFNC.

Background: Elderly patients with coronavirus disease 2019 (COVID-19) have a high disease severity and mortality. However, the use of the frailty scale and severity score to predict in-hospital mortality in the elderly is not well established. Therefore, in this study, we investigated the use of these scores in COVID-19 cases in the elderly. Methods: This multicenter retrospective study included severe COVID-19 patients admitted to seven hospitals in Republic of Korea from February 2020 to February 2021. We evaluated patients' Acute Physiology and Chronic Health Evaluation (APACHE) II score; confusion, urea nitrogen, respiratory rate, blood pressure, 65 years of age and older (CURB-65) score; modified early warning score (MEWS); Sequential Organ Failure Assessment (SOFA) score; clinical frailty scale (CFS) score; and Charlson comorbidity index (CCI). We evaluated the predictive value using receiver operating characteristic (ROC) curve analysis. Results:The study included 318 elderly patients with severe COVID-19 of whom 237 (74.5%) were survivors and 81 (25.5%) were non-survivors. The non-survivor group was older and had more comorbidities than the survivor group. The CFS, CCI, APACHE II, SOFA, CURB-65, and MEWS scores were higher in the non-survivor group than in the survivor group. When analyzed using the ROC curve, SOFA score showed the best performance in predicting the prognosis of elderly patients (area under the curve=0.766, P < 0.001). CFS and SOFA scores were associated with in-hospital mortality in the multivariate analysis. Conclusions:The SOFA score is an efficient tool for assessing in-hospital mortality in elderly patients with severe COVID-19.

SARS-CoV-2 infection was confirmed by reverse-transcriptase polymerase chain reaction assay; an oxygen saturation level of 94% or less on room air or a need for oxygen support was defined as severe .Background/Aims: Secondary infection with influenza virus occurs in critically ill patients and is associated with substantial morbidity and mortality; however, there is limited information about it in patients with severe coronavirus disease 2019 . Thus, we investigated the clinical outcomes of and risk factors for secondary infections in patients with severe COVID-19. Methods: This study included patients with severe COVID-19 who were admitted to seven hospitals in South Korea between February 2020 to February 2021. Multivariate logistic regression analyses were performed to assess factors associated with the risk of secondary infections. Results: Of the 348 included patients, 104 (29.9%) had at least one infection. There was no statistically significant difference in the 28-day mortality (17.3% vs. 12.3%, p = 0.214), but in-hospital mortality was higher (29.8% vs. 15.2%, p = 0.002) in the infected group than in the non-infected group. The risk factors for secondary infection were a high frailty scale (odds ratio [OR], 1.314; 95% confidence interval [CI], 1.123 to 1.538; p = 0.001), steroid use (OR, 3.110; 95% CI, 1.164 to 8.309; p = 0.024), and the application of mechanical ventilation (OR, 4.653; 95% CI, 2.533 to 8.547; p < 0.001). Conclusions: In-hospital mortality was more than doubled in patients with severe COVID-19 and secondary infections. A high frailty scale, the use of steroids and application of mechanical ventilation were risk factors for secondary infection.

Background: Vitamin C is a well-known antioxidant and essential cofactor for numerous biological reactions. Several studies reported that vitamin C can improve the symptoms and prognosis of patients with sepsis and respiratory infection. We aimed to examine the effect of vitamin C when used in viral pneumonia patients with severe respiratory failure. Methods: Total 201 patients with viral pneumonia were included, of them 35 patients used vitamin C. We performed a statistical analysis through a propensity score matching of the age and baseline characteristics of these patients. Results: There were differences between the vitamin C group and non-vitamin C group in terms of age (60±15 vs. 66±14, P=0.03), extracorporeal membrane oxygenation (28.6% vs. 5.4%, P<0.001), and procalcitonin (3±8 vs. 9±23, P=0.02). The 28-day mortality was not different between the two groups (20.0% vs. 24.7%, P=0.33). In the propensity-matched group, the 28-day mortality was not significantly different between the two groups (20.0% vs. 37.1%, P=0.07). Moreover, no difference was observed in shock reversal within 14 days (45.7% vs. 25.7%, P=0.08) and recovery after acute kidney injury (52.9% vs. 66.7%, P=0.41) between the two groups. Vitamin C was not a prognostic factor for 28-day mortality (P=0.33). Conclusions: In this study adjunctive intravenous vitamin C therapy alone was not associated with improvement of the 28-day mortality and prognosis in patients with severe viral pneumonia with respiratory failure.

Background: The diagnosis and prediction of prognosis are important in patients with sepsis, and presepsin is helpful. In this study, we aimed to examine the usefulness of presepsin in predicting the prognosis of sepsis in Korea. Methods: Patients diagnosed with sepsis according to the sepsis-3 criteria were recruited into the study and classified into surviving and non-surviving groups based on in-hospital mortality. A total of 153 patients (32 and 121 patients with sepsis and septic shock, respectively) were included from July 2019 to August 2020. Results: Among the 153 patients with sepsis, 91 and 62 were in the survivor and non-survivor groups, respectively. Presepsin (p =0.004) and lactate (p =0.003) levels and the sequential organ failure assessment (SOFA) score (p <0.001) were higher in the non-survivor group. Receiver operating characteristic curve analysis revealed poor performances of presepsin and lactate in predicting the prognosis of sepsis (presepsin: area under the curve [AUC] =0.656, p =0.001; lactate: AUC =0.646, p =0.003). The SOFA score showed the best performance, with the highest AUC value (AUC =0.751, p <0.001). The prognostic cutoff point for presepsin was 1,176 pg/mL. Presepsin levels higher than 1,176 pg/mL (odds ratio [OR], 3.352; p <0.001), higher lactate levels (OR, 1.203; p =0.003), and higher SOFA score (OR, 1.249; p <0.001) were risk factors for in-hospital mortality. Conclusion: Presepsin levels were higher in non-survivors than in survivors. Thus, presepsin may be a valuable biomarker in predicting the prognosis of sepsis.