Investigating the appropriate adenosine deaminase cutoff value for the diagnosis of tuberculous pleural effusion in a country with decreasing TB burden.

As the burden of tuberculosis (TB) in South Korea decreases while that of malignancy increases with an aging society, the composition of etiology for pleural effusion is changing. The aim of this study was to investigate the diagnostic value of adenosine deaminase (ADA) for diagnosis of tuberculous pleural effusion (TPE) in this circumstance. Medical records of patients who underwent medical thoracoscopy from May 2015 to September 2020 in Incheon St. Mary Hospital, Korea were retrospectively reviewed. TPE was diagnosed if one of the following criteria was met: (1) granuloma in pleura, (2) positive TB polymerase chain reaction or culture in pleural fluid or tissue with non-specific pathologic findings in pleura, or (3) bacteriologically confirmed pulmonary TB with non-specific pathologic findings in pleura. A total of 292 patients, including 156 with malignant pleural effusion (MPE), 52 with TPE, and 84 with other benign effusion, were analyzed. Among 206 patients with lymphocyte dominant pleural effusion, the area under receiver characteristic curve of ADA for diagnosis of TPE was 0.971. The sensitivity and specificity of a current cutoff value of 40 IU/L were 1.00 and 0.61, respectively, whereas those of a raised cutoff value of 70 IU/L were 0.93 and 0.93, respectively. Among 54 patients with ADA levels of 40-70 IU/L, 30 (55.6%) patients were diagnosed as MPE, 21 (38.9%) as other benign effusion, and only 3 (5.6%) as TPE. Caution is needed in clinical diagnosis of TPE with current ADA cutoff value in countries with decreasing TB incidence, due to many false positive cases.

Role of Nuclear Factor Erythroid 2‒Related Factor 2 in Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation due to chronic airway inflammation and destruction of the alveolar structure from persistent exposure to oxidative stress. The body has various antioxidant mechanisms for efficiently coping with such oxidative stress. The nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) is a representative system. Dysregulation of the Nrf2-ARE pathway is responsible for the development and promotion of COPD. Furthermore, COPD severity is also closely related to this pathway. There has been a clinical impetus to use Nrf2 for diagnostic and therapeutic purposes. Therefore, in this work, we systematically reviewed the clinical significance of Nrf2 in COPD patients, and discuss the value of Nrf2 as a potential COPD biomarker.

Impact of smoking amount on clinicopathological features and survival in non-small cell lung cancer.

BACKGROUND: Screening for early detection of lung cancer has been performed in high-risk individuals with smoking history. However, researches on the distribution, clinical characteristics, and prognosis of these high-risk individuals in an actual cohort are lacking. Thus, the objective of this study was to retrospectively review characteristics and prognosis of patients with smoking history in an actual lung cancer cohort. METHODS: The present study used the lung cancer cohort of the Catholic Medical Centers at the Catholic University of Korea from 2014 to 2017. Patients with non-small cell lung cancer were enrolled. They were categorized into high and low-risk groups based on their smoking history using the national lung screening trial guideline. Distribution, clinical characteristics, and survival data of each group were estimated. RESULTS: Of 439 patients, 223 (50.8%) patients were in the high-risk group. Patients in the high-risk group had unfavorable clinical characteristics and tumor biologic features. Overall survival of the high-risk group was significantly shorter than that of the low-risk group with both early (I, II) and advanced stages (III, IV). In multivariate analysis, heavy smoking remained one of the most important poor clinical prognostic factors in patients with lung cancer. It showed a dose-dependent relationship with patients' survival. CONCLUSIONS: High-risk individuals had poor clinical outcomes. Patients' prognosis seemed to be deteriorated as smoking amount increased. Therefore, active screening and clinical attention are needed for high-risk individuals.

Effects of chronic intermittent hypoxia caused by obstructive sleep apnea on lipopolysaccharide-induced acute lung injury.

AIM OF THE STUDY: Obstructive sleep apnea (OSA) is a common disease associated with significant morbidity and mortality. Sleep quality is an important issue; some patients with acute lung injury (ALI) have underlying OSA. However, the potential influences of OSA on ALI have not been reported until now. In this study, we evaluated the impact of preceding intermittent hypoxia (IH), a typical characteristic of OSA, on lipopolysaccharide (LPS)-induced ALI in a mouse model. METHODS: C57BL/6J mice were randomly divided into four groups: room air-control (RA-CTL), intermittent hypoxia-control (IH-CTL), room air-lipopolysaccharide (RA-LPS), and intermittent hypoxia-lipopolysaccharide (IH-LPS) groups. The mice were exposed to RA or IH (20 cycles/h, FiO2 nadir 7 ± 0.5%, 8 h/day) for 30 days. The LPS groups received intratracheal LPS on day 28. RESULTS: The IH-LPS group tended to exhibit more severe inflammation, fibrosis, and oxidative stress compared to the other groups, including the RA-LPS group. Total cell, neutrophil, and eosinophil counts in bronchoalveolar lavage fluid increased significantly in the IH-LPS group compared to the RA-LPS group. Compared to the RA-LPS group, the hydroxyproline level increased significantly in the IH-LPS group. In addition, the IH-LPS group exhibited significantly more terminal deoxynucleotidyl transferase dUTP nick end labeled-positive cells compared to the RA-LPS group. CONCLUSIONS: We found that prior IH may negatively impact LPS-induced ALI in a mouse model. This result suggests that ALI in patients with OSA may be more of a concern. Further research into the mechanisms underlying the effects of IH on ALI is needed.

Utilization of a rapid response team and associated outcomes in patients with malignancy.

BACKGROUND: Recent advances in diagnosis and treatment have improved long-term outcomes in cancer patients. As a result, the requirement for a rapid response team (RRT) for cancer patients is also increasing. This study aimed to analyze utilization of an RRT and the associations between related factors and mortality in a population of cancer patients. METHODS: This retrospective cohort study included hospitalized patients at a single academic medical center in Seoul, Korea, who required RRT activation during a 6-year period from June 2013 to December 2018. RESULTS: Overall, 164 of the 457 patients who met the above criteria were cancer patients, and they had a significantly higher Charlson comorbidity score than the non-cancer patients (5.0 vs. 7.0, P<0.001). A significantly larger proportion of cancer patients required intensive care unit transfer (51.8% vs. 41.0%, P=0.032). Cancer patients also had significantly higher in-hospital mortality compared with other patients (39.6% vs. 10.9%, P<0.001). Furthermore, presence of cancer was independently associated with in-hospital mortality (adjusted odds ratio [OR], 2.09; 95% confidence interval [CI], 1.11 to 3.93). Among cancer patients, higher Acute Physiology and Chronic Health Evaluation (APACHE) II at the time of RRT activation was significantly associated with in-hospital mortality regardless of malignancy (adjusted OR, 1.08; 95% CI, 1.01 to 1.15). CONCLUSIONS: Cancer patients requiring RRT activation have significantly higher rates of inhospital mortality than patients not using RRT. Higher severity score at the time of RRT activation in patients with malignancy was significantly associated with in-hospital mortality.

Intermittent hypoxia exacerbates tumor progression in a mouse model of lung cancer.

The purpose of this study was to evaluate whether obstructive sleep apnea (OSA)-related chronic intermittent hypoxia (CIH) influences lung cancer progression and to elucidate the associated mechanisms in a mouse model of lung cancer. C57/BL6 mice in a CIH group were exposed to intermittent hypoxia for two weeks after tumor induction and compared with control mice (room air). Hypoxia inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF) and metastasis-related matrix metalloproteinases (MMP) were measured. The expression levels of several hypoxia-related pathway proteins including HIF-1α, Wnt/ß-catenin, the nuclear factor erythroid 2-related factor 2 (Nrf2) and mammalian target of rapamycin-ERK were measured by western blot. The number (P < 0.01) and volume (P < 0.05) of tumors were increased in the CIH group. The activity of MMP-2 was enhanced after CIH treatment. The level of VEGF was increased significantly in the CIH group (p < 0.05). ß-catenin and Nrf2 were translocated to the nucleus and the levels of downstream effectors of Wnt/ß-catenin signaling increased after IH exposure. CIH enhanced proliferative and migratory properties of tumors in a mouse model of lung cancer. ß-catenin and Nrf2 appeared to be crucial mediators of tumor growth.

Factors associated with discrepancy between fresh frozen and permanent biopsy from medical thoracoscopy: single center analysis of 172 medical flexible thoracoscopy cases.

BACKGROUND: Frozen sections prepared during medical thoracoscopy (MT) have precise diagnostic ability in pleural pathology and may assist in decision-making before pleurodesis. The present study evaluated the diagnostic sensitivity of frozen sections from flex-rigid MT, and further evaluated clinical parameters for their association with a discrepancy between frozen sections and permanent paraffin sections. METHODS: This retrospective study evaluated 172 patients who underwent flex-rigid MT between February 2017 and November 2019 at Incheon Saint Mary's Hospital. RESULTS: Of the 172 patients, 85 were pathologically diagnosed with malignancy based on permanent paraffin sections. An accurate diagnosis by fresh frozen section was feasible in 88.2% of the cases compared to the permanent paraffin sections. Among the 85 patients, 75 had malignancies in frozen sections, while 10 patients showed otherwise. In the 85 malignant cases, age, sex, the volume of effusion, thoracoscopic findings, as well as the final pathological diagnosis (lung vs. non-lung origin) were included in univariate analysis for an association with non-malignant frozen section results. High adhesion grade and malignancy other than lung cancer were significant factors associated with frozen section negative cases in a multivariable analysis. CONCLUSIONS: Taking fresh frozen sections during MT using a flex-rigid bronchoscope is a useful diagnostic modality with reliable sensitivity for malignancy. However, if the pre-procedural diagnosis is likely to be a malignancy other than lung cancer, and if severe adhesions are present in the pleural cavity, the final pathological confirmation should be determined based on permanent paraffin sections, not only on fresh frozen sections.

Chronic nicotine exposure affects programmed death-ligand 1 expression and sensitivity to epidermal growth factor receptor-tyrosine kinase inhibitor in lung cancer.

BACKGROUND: Smoking histories are independently associated with poor response to epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) patients with activating EGFR mutations. The aim of the present study was to determine the effect of nicotine exposure on programmed death-ligand 1 (PD-L1) expression in EGFR mutant lung cancer cells. METHODS: Human lung adenocarcinoma PC9 cells were exposed to 1 µM nicotine for 3 months designated as PC9/N, and cells were stimulated with gefitinib (0, 0.1, or 1 µM) for 48 hrs. Cell viability by the MTT assay and morphological changes by immunofluorescence staining were assessed. The protein expression of EGFR, mTOR, AKT, α1-nicotine acetylcholine receptor (nAchR) and PD-L1 were measured by Western blot. Gene expression of α1-nAchR and PD-L1 were examined by RT-PCR. Intratumoral levels of PD-L1 expression were compared according to the burden of smoking dosage in 54 EGFR mutant lung cancer patients. RESULTS: Cellular growth was inhibited by treatment with gefitinib, and PC9 cells were significantly more sensitive to gefitinib than PC9/N cells. Pleomorphic appearance with atypical nuclei and to be detached and shrunken with condensed nuclei in PC9 than PC9/N cells. The gene expression level of α1-nAchR and PD-L1 gene were higher in PC9/N cells compared to those in PC9 cells after treatment with gefitinib. Phosphorylation levels of EGFR, mTOR, AKT and PD-L1 level were decreased by gefitinib in PC9/N cells, which was to a lesser extent than that in PC9 cells. In tumors, heavy smokers (≥30 PY) showed 28.5% of ≥50% PD-L1 tumor proportion score (TPS) while light smoker and never smokers had 12.5% and 9.7% of ≥50% PD-L1 TPS, respectively. However, there was no statistical significance (P value =0.628). CONCLUSIONS: Chronic nicotine exposure could increase PD-L1 expression related to intrinsic resistance to EGFR-TKI in NSCLC patients harboring activating EGFR mutation. Considering the clinical importance of inevitable EGFR resistance, further studies regarding the role of anti-PD-1/PD-L1 treatment are needed, especially in EGFR mutant smokers.

Effect of COPD on symptoms, quality of life and prognosis in patients with advanced non-small cell lung cancer.

BACKGROUND: Many studies have reported the prevalence of chronic obstructive pulmonary disease (COPD) and its effects and prognosis in patients with lung cancer, but few have considered quality of life and survival of patients with lung cancer according to severity of airway obstruction. This study investigated the presence of COPD and the severity of airway obstruction in patients with non-small cell lung cancer (NSCLC), and analyzed how these factors affected symptoms, quality of life, and prognosis. METHODS: We retrospectively reviewed the prospective lung cancer database of the Catholic Medical Centers at the Catholic University of Korea from 2014 to 2017. We enrolled patients with advanced NSCLC and evaluated quality of life using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-C30. We also estimated pulmonary function and analyzed survival data. RESULTS: Of the 337 patients with advanced NSCLC, 170 (50.5%) had COPD and 167 (49.5%) did not. Significant differences were observed in symptoms between the two groups. The COPD group complained of more symptoms, such as cough, sputum, and dyspnea, than those in the non-COPD group. The distribution according to the severity of obstruction in the COPD group was as follows: Grade 1 (FEV1 ≥ 80%) 35 patients (20.6%), Grade 2 (50% ≤ FEV1 < 80%) 103 patients (60.6%), Grade 3 (30% ≤ FEV1 < 50%) 24 patients (14.1%), and Grade 4 (FEV1 < 30%) 8 patients (4.7%). The presence of COPD did not affect overall quality of life in patients with NSCLC, but as the airway obstruction increased, physical function decreased, and fatigue and dyspnea were more frequent. The overall median survival of the COPD group was shorter than that of the non-COPD group (median survival, 224 vs. 339 days, p = 0.035). CONCLUSIONS: In this study, a high prevalence of COPD was found among patients with advanced NSCLC, and COPD patients complained about various symptoms and had diminished quality of life in several sectors. Therefore, it is necessary to actively evaluate quality of life, lung function, and symptoms in patients with lung cancer and reflect them in the treatment and management plans of these patients.

Accuracy and Reliability of Internet Resources Providing Information on Obstructive Sleep Apnea.

STUDY OBJECTIVES: To evaluate the readability, content, and quality of internet information about obstructive sleep apnea (OSA). METHODS: Three major search engines (Google, Yahoo, and Bing) were used to retrieve the first 200 hits for the term "sleep apnea." The website contents were assessed using established guidelines, while the website quality was evaluated using the validated DISCERN instrument and Journal of the American Medical Association benchmarks. RESULTS: In total, 243 websites met the inclusion criteria for this study. The websites were divided into five categories: scientific resource, foundation, news/ media report, commercial website, and personal commentary. The mean Flesch-Kincaid grade level, which indicated the readability of the websites, was 7.5. The quality of most websites was poor, with news/media reports and commercial websites exhibiting poorer quality than the others. The Health On the Net (HON) code, which certifies the reliability and credibility of online content regarding human health, was applied only to 14.3% websites; the reliability of all these websites was poor. The content score for the diagnosis and management of OSA was lower for news/media reports and commercial websites than for scientific resources. News/media reports exhibited the worst content scores. CONCLUSIONS: Our findings suggest that most online health resources regarding OSA are not reliable and are inaccurate. Health care providers should be aware of the high variability in online information concerning OSA. COMMENTARY: A commentary on this article appears in this issue on page 1643.

The relationship between sleep disturbance and health status in patients with COPD.

Introduction: The detection of insomnia in patients with COPD is assumed to be significantly lower than the actual prevalence. In this study, we investigated the prevalence of insomnia and the relationship between insomnia and health status in patients with COPD using two fairly simple and straightforward questionnaires: COPD assessment test (CAT) and insomnia severity index (ISI). Patients and methods: A cross-sectional study was conducted using data from patients undergoing treatment for COPD at St Paul's Hospital, The Catholic University of Korea, between December 2015 and August 2016. Patients were classified into three groups according to the ISI score: a "clinical insomnia" group (ISI≥15), a "subthreshold insomnia" group (ISI 8-15), and a "non-insomnia" group (ISI<8). Clinical parameters including past medical history, pulmonary function tests, and questionnaire data were collected and analyzed. Results: A total of 192 patients were recruited, of which 25.0% were found to have clinical insomnia (ISI≥8). Insomnia severity was related to all CAT component items except for cough, and patients with higher CAT scores generally had more severe insomnia. Logistic regression analysis revealed that CAT score was significantly associated with insomnia in these patients (odds ratio, 1.23; 95% CI, 1.13-1.34; p<0.0001). CAT score was also a significant predictor of insomnia (area under receiver operating characteristic curve, 0.779; p<0.001). The optimal predictive cutoff value was a CAT score >14, giving a sensitivity and specificity of 66.7% and 71.5%, respectively. Conclusion: CAT score was closely related to insomnia severity in patients with COPD. The use of CAT scores to assess for the presence and severity of insomnia in these patients may allow for better detection and management and improve clinical practice.

Clinical significance of nuclear factor erythroid 2-related factor 2 in patients with chronic obstructive pulmonary disease.

Background/Aims: Several studies have identified a role for nuclear factor erythroid 2-related factor 2 (Nrf2) in the development of chronic obstructive pulmonary disease (COPD). However, the relationship between the plasma Nrf2 level and the extent of systemic inflammation associated with COPD status remains unclear. METHODS: Patients diagnosed with COPD were recruited from St. Paul's Hospital, The Catholic University of Korea, between July 2009 and May 2012. Patients were classified into two groups according to the severity of their symptoms on initial presentation, a COPD-stable group (n = 25) and a COPD-exacerbation group (n = 30). Seventeen patients were enrolled as a control group (n = 17). The plasma levels of Nrf2 and other systemic inf lammatory biomarkers, including interleukin 6 (IL-6), surfactant protein D (SP-D), and C-reactive protein (CRP), were measured. We collected clinical data including pulmonary function test results, and analyzed the relationships between the biomarker levels and the clinical parameters. RESULTS: Plasma Nrf2 and CRP levels significantly increased in a stepwise manner with an increase in inflammatory status (control vs. COPD-stable vs. COPD-exacerbation) (p = 0.002, p < 0.001). Other biomarkers of systemic inflammation (IL-6, SP-D) exhibited similar tendencies, but significant differences were not apparent. Furthermore, we observed negative correlations between the plasma level of Nrf2 and both the forced expiratory volume in 1 second (FEV1) (r = -0.339, p = 0.015) and the forced expiratory ratio (FEV1/forced vital capacity [FVC]) (r = -0.342, p = 0.014). However, CRP level was not correlated with any measured parameter. Conclusions: Plasma Nrf2 levels gradually increased in line with disease severity and the extent of systemic inflammation in patients with COPD.

Dyspnea as a Prognostic Factor in Patients with Non-Small Cell Lung Cancer.

PURPOSE: To investigate associations between dyspnea and clinical outcomes in patients with non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: From 2001 to 2014, we retrospectively reviewed the prospective lung cancer database of St. Paul's Hospital at the Catholic University of Korea. We enrolled patients with NSCLC and evaluated symptoms of dyspnea using modified Medical Research Council (mMRC) scores. Also, we estimated pulmonary functions and analyzed survival data. RESULTS: In total, 457 NSCLC patients were enrolled, and 259 (56.7%) had dyspnea. Among those with dyspnea and whose mMRC scores were available (109 patients had no mMRC score), 85 (56.6%) patients had an mMRC score <2, while 65 (43.3%) had an mMRC score ≥2. Significant decreased pulmonary functions were observed in patients with dyspnea. In multivariate analysis, aging, poor performance status, advanced stage, low forced expiratory volume in 1 second (%), and an mMRC score ≥2 were found to be significant prognostic factors for patient survival. CONCLUSION: Dyspnea could be a significant prognostic factor in patients with NSCLC.

Smoking habits and nicotine dependence of North Korean male defectors.

BACKGROUND/AIMS: The smoking rates and patterns in the North Korean population are not well known. More than 20,000 North Korean defectors have settled in South Korea; thus, we can estimate the current North Korean smoking situation using this group. METHODS: All North Korean defectors spend their first 3 months in a South Korean facility learning to adapt to their new home. We retrospectively analyzed the results from a questionnaire conducted among North Korean male defectors in this facility from August 2012 to February 2014. RESULTS: Of 272 men, 84.2% were current smokers, 12.5% were ex-smokers, and 3.3% were non-smokers. The mean age of this group was 35.9 ± 11.3 years, and smoking initiation occurred at a mean age of 18.2 ± 4.7 years. Among the subjects, 78.1% had a family member who smoked. Of the 221 current smokers, 67.4% responded that they intended to quit smoking. Fagerström test and Kano test for social nicotine dependence (KTSND) results for current smokers were 3.35 ± 2.26 and 13.76 ± 4.87, respectively. Question 9 on the KTSND (doctors exaggerate the ill effects of smoking) earned a significantly higher score relative to the other questions and a significantly higher score in current smokers compared with non-smokers. CONCLUSIONS: The smoking rate in North Korean male defectors was higher than that indicated previously. However, interest in smoking cessation was high and nicotine dependence was less severe than expected. Further investigation is needed to identify an efficient method for North Korean smokers to stop smoking.

Predictors for diabetic retinopathy in normoalbuminuric people with type 2 diabetes mellitus.

BACKGROUND: Previous studies have reported that microalbuminuria is an independent risk factor for the prevalence of diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (DM). For this reason, the clinical significance of DR in normoalbuminuric type 2 DM patients may be overlooked. The aim of this study was to investigate the prevalence of DR and predictors for DR in normoalbuminuric patients with type 2 DM. METHODS: A total 310 patients with type 2 DM and normoalbuminuria, who were referred to the Department of Ophthalmology for screening of DR were included in this study. DR was clinically graded according to the International Clinical Diabetic Retinopathy guidelines. The urinary albumin excretion rate (UAER) was assessed via 24-hour urine collection and measured by immunoturbidimetric assay. Normoalbuminuria was defined as a UAER < 20 µg/min in 2 out of 3 consecutive tests taken within 2-3 months. RESULTS: DR of any grade was present in 64/310 (20.7 %) patients. Mild non-proliferative diabetic retinopathy (NPDR) was most prevalent in patients with DR of any grade (36/64, 56 %). The duration of diabetes (OR 1.01, 95 % CI, 1.01 - 1.02, p < 0.001), hemoglobin levels (OR 0.73, 95 % CI, 0.59 - 0.91, p = 0.004) and a higher tertile of UAER (OR 4.04, 95 % CI, 1.71 - 9.57, p = 0.001) had independently significant association with DR. NPDR as well as PDR was more prevalent in patients with higher tertile of UAER compared with those with lower tertile of UAER (NPDR, p = 0.002 and PDR, p = 0.027, respectively). CONCLUSIONS: Our findings suggest that patients with normoalbuminuric type 2 DM also require close monitoring for the early detection of DR, especially if they have a higher UAER, longer duration of diabetes, or lower hemoglobin levels.