Prevalence and impact of airway diseases on clinical outcomes in idiopathic pulmonary fibrosis.

BACKGROUND/AIMS: The prevalence and effects of airway diseases, including asthma, eosinophilic bronchitis (EB), chronic obstructive pulmonary disease (COPD), and asthma-COPD overlap (ACO) have not been thoroughly studied in patients with idiopathic pulmonary fibrosis (IPF). This study aimed to evaluate the prevalence of airway diseases in patients with IPF and to identify the differences in symptoms based on the presence of airway diseases. METHODS: This single-institution prospective cohort study was conducted from June 2017 to September 2018, at the Seoul National University Hospital. Spirometry with bronchodilator, methacholine bronchial provocation test, induced sputum with eosinophil stain, and exhaled nitric oxide were performed to confirm the presence of airway disease. The modified Medical Research Council (mMRC) dyspnea scale, COPD assessment test (CAT), St. George's Respiratory Questionnaire (SGRQ), EuroQol-5 dimension (EQ-5D) index, and cough-specific quality of life questionnaire (CQLQ) data were collected to assess symptom severity. RESULTS: Total 147 patients with IPF were screened, and 70 patients were analyzed. The prevalence of airway diseases in the participants was as follows: 5.0% had COPD, 1.7% had asthma, 3.3% had ACO, and 1.7% had EB. The mMRC, CAT, SGRQ, EQ-5D, and CQLQ scores did not differ regardless of combined airway disease. After 3 months, the SGRQ (p = 0.028) and CQLQ (p = 0.030) scores were significantly higher in patients with airway disease than in those without. CONCLUSION: The prevalence of airway diseases in patients with IPF is low, but when airway diseases are accompanied by IPF, symptom severity and quality of life may worsen rapidly.

Validation of age, PaO2/FlO2 and plateau pressure score in Korean patients with acute respiratory distress syndrome: a retrospective cohort study.

BACKGROUND: A predictive scoring system for acute respiratory distress syndrome (ARDS) patients, which incorporates age, PaO2/FlO2, and plateau pressure, APPS, was developed recently. It was validated externally in a Caucasian population but has not been studied in Asian populations. The aim of this study was to validate APPS in Korean ARDS patients. METHODS: We retrospectively reviewed the medical records of patients who were diagnosed with ARDS using the Berlin criteria and admitted to the medical ICU at Seoul National University Hospital from January 2015 to December 2016. The validation of the APPS was performed by evaluating its calibration and predictive accuracy. Its calibration was plotted and quantified using the Hosmer-Lemeshow test. Its predictive accuracy was assessed by calculating the area under the receiver operating characteristics (AUC-ROC) curve. RESULTS: A total of 116 patients were analyzed, 32 of whom survived. Of the 116 patients, 11 (9.5%) were classified as APPS grade 1 (score 3-4), 88 (75.9%) as grade 2 (score 5-7) and 17 (14.6%) as grade 3 (score 8-9). In-hospital mortality was 27.3% for grade 1, 73.9% for grade 2 and 94.1% for grade 3 (P for trend < 0.001). The APPS was well calibrated (Hosmer-Lemeshow test, P = 0.578) and its predictive accuracy was acceptable (AUC-ROC 0.704, 95% confidence interval 0.599-0.809). CONCLUSIONS: The APPS predicted in-hospital mortality in Korean patients with ARDS with similar power to its application in a Western population and with acceptable predictive accuracy. TRIAL REGISTRATION: Retrospectively registered.

Sleep duration and health-related quality of life in Korean adults: 2007-2015 Korea National Health and Nutrition Examination Survey.

PURPOSE: To evaluate the association of sleep duration with health-related quality of life (HRQOL) and examine the influence of age, sex, and common comorbidities on this association. METHODS: Using appropriate survey design, we analyzed 50,181 adults who participated in the 2007-2015 Korea National Health and Nutrition Examination Survey. Participants were categorized into five groups according to self-reported sleep duration ≤ 5 (short sleeper), 6, 7, 8, and ≥ 9 h (long sleeper). HRQOL was measured with the European Quality of Life-5 Dimensions (EQ-5D) index and visual analogue scale (VAS). RESULTS: In multiple linear regression, short sleep duration was associated with lower EQ-5D index (ß = - 0.024; 95% confidence interval [CI], - 0.027 to - 0.021) and lower EQ-VAS (ß = - 3.0; 95% CI, - 3.7 to - 2.3), and long sleep duration was associated with lower EQ-5D index (ß = - 0.016; 95% CI, - 0.021 to - 0.011) and lower EQ-VAS (ß = - 2.2; 95% CI, - 3.1 to - 1.3) compared with 7-h sleepers. Old-age (≥ 65 years old) short and long sleepers had significantly lower EQ-5D index than those of < 65 years old. When separated according to sex, men with long sleep and women with short sleep showed the lowest EQ-5D index. Short and long sleepers with hypertension, diabetes, hypercholesterolemia, cardiovascular disease, or depression showed significantly lower EQ-5D index than those without comorbidities. CONCLUSIONS: Extreme sleep duration was associated with poor HRQOL. Short and long sleepers with old age and comorbidities had significantly lower HRQOL than those without such conditions.

Rapid Muscle Loss Negatively Impacts Survival in Critically Ill Patients With Cirrhosis.

PURPOSE: To assess the impact of rapid muscle loss before admission to intensive care unit (ICU) in critically ill patients with cirrhosis. MATERIALS AND METHODS: Patients with cirrhosis who had undergone 2 or more recent computed tomography scans before admission to the medical ICU were included. Muscle cross-sectional area at the level of the third lumbar vertebra was quantified using OsiriX software. The rate of muscle mass change and skeletal muscle index (SMI) were also calculated. Multivariable Cox proportional hazards regression was used to evaluate the association between muscle loss and mortality. RESULTS: Among 125 patients, 113 (90.4%) patients were classified as having sarcopenia. The mean body mass index was 22.6 (3.9) kg/m2. Thirty-nine (31.2%) patients were within the normal range for muscle mass change, while 86 (68.8%) patients demonstrated rapid decline in muscle mass before admission to the ICU. Patients with rapid muscle loss showed high ICU mortality (59.3%) and in-hospital mortality (77.9%). Multivariate Cox analysis showed that ICU mortality and in-hospital mortality were independently associated with malignancy, Acute Physiology and Chronic Health Evaluation (APACHE) II score, SMI, and rapid muscle loss. CONCLUSION: Rapid muscle decline is correlated with increased ICU mortality and in-hospital mortality in critically ill patients with cirrhosis.

Mortality risk and causes of death in patients with non-cystic fibrosis bronchiectasis.

BACKGROUND: All-cause mortality risk and causes of death in bronchiectasis patients have not been fully investigated. The aim of this study was to compare the mortality risk and causes of death between individuals with bronchiectasis and those without bronchiectasis. METHODS: Patients with or without bronchiectasis determined based on chest computed tomography (CT) at one centre between 2005 and 2016 were enrolled. Among the patients without bronchiectasis, a control group was selected after applying additional exclusion criteria. We compared the mortality risk and causes of death between the bronchiectasis and control groups without lung disease. Subgroup analyses were also performed according to identification of Pseudomonas or non-tuberculous mycobacteria, airflow limitation, and smoking status. RESULTS: Of the total 217,702 patients who underwent chest CT, 18,134 bronchiectasis patients and 90,313 non-bronchiectasis patients were included. The all-cause mortality rate in the bronchiectasis group was 1608.8 per 100,000 person-years (95% confidence interval (CI), 1531.5-1690.0), which was higher than that in the control group (133.5 per 100,000 person-years; 95% CI, 124.1-143.8; P < 0.001). The bronchiectasis group had higher all-cause (adjusted hazard ratio (aHR), 1.26; 95% CI, 1.09-1.47), respiratory (aHR, 3.49; 95% CI, 2.21-5.51), and lung cancer-related (aHR, 3.48; 95% CI, 2.33-5.22) mortality risks than the control group. In subgroup analysis, patients with airflow limitation and ever smokers showed higher all-cause mortality risk among bronchiectasis patients. Therefore, we observed significant interrelation between bronchiectasis and smoking, concerning the risks of all-cause mortality (P for multiplicative interaction, 0.030, RERI, 0.432; 95% CI, 0.097-0.769) and lung cancer-related mortality (RERI, 8.68; 95% CI, 1.631-15.736). CONCLUSION: Individuals with bronchiectasis had a higher risk of all-cause, respiratory, and lung cancer-related mortality compared to control group. The risk of all-cause mortality was more prominent in those with airflow limitation and in ever smokers.

Role of ethambutol and rifampicin in the treatment of Mycobacterium avium complex pulmonary disease.

BACKGROUND: A three-drug regimen (macrolide, ethambutol, and rifampicin) is recommended for the treatment of Mycobacterium avium complex pulmonary disease (MAC-PD). Although macrolide has proven efficacy, the role of ethambutol and rifampicin in patients without acquired immune deficiency syndrome is not proven with clinical studies. We aimed to clarify the roles of ethambutol and rifampicin in the treatment of MAC-PD. METHODS: Patients treated for MAC-PD between March 1st, 2009 and October 31st, 2018 were reviewed retrospectively. Rates of culture conversion, microbiological cure, treatment failure, and recurrence were compared according to the maintenance (≥6 months) of ethambutol or rifampicin with macrolide. RESULTS: Among the 237 patients, 122 (51.5%) maintained ethambutol and rifampicin with macrolide, 58 (24.5%) maintained ethambutol and macrolide, 32 (13.5%) maintained rifampicin and macrolide, and 25 (10.6%) maintained macrolide only. Culture conversion was reached for 190/237 (80.2%) patients and microbiological cure was achieved for 129/177 (72.9%) who completed the treatment. Treatment failure despite ≥12 months of treatment was observed in 66/204 (32.4%), and recurrence was identified in 16/129 (12.4%) who achieved microbiological cure. Compared with maintenance of macrolide only, maintenance of ethambutol, rifampicin or both with macrolide were associated with higher odds of culture conversion [odds ratio (OR), 95% confidence interval (CI): 18.06, 3.67-88.92; 15.82, 2.38-105.33; and 17.12, 3.93-74.60, respectively]. Higher odds of microbiological cure were associated with maintenance of both ethambutol and rifampicin with macrolide (OR, 95% CI: 5.74, 1.54-21.42) and macrolide and ethambutol (OR, 95% CI: 5.12, 1.72-15.24) but not macrolide and rifampicin. Maintenance of both ethambutol and rifampicin with macrolide was associated with lower odds of treatment failure (OR, 95% CI: 0.09, 0.01-0.53) compared with macrolide only, while maintenance of one of these with macrolide was not. Maintenance of both ethambutol and rifampicin or one of these with macrolide did not decrease the probability of recurrence when compared with macrolide only. CONCLUSIONS: Maintenance (≥6 months) of ethambutol and rifampicin with macrolide was associated with the most favorable treatment outcomes among patients with MAC-PD. Given the association between ongoing ethambutol use and microbiological cure, clinicians should maintain ethambutol unless definite adverse events develop.

Reduction of PaCO2 by high-flow nasal cannula in acute hypercapnic respiratory failure patients receiving conventional oxygen therapy.

BACKGROUND: It has been suggested that a high-flow nasal cannula (HFNC) could help to remove carbon dioxide (CO2) from anatomical dead spaces, but evidence to support that is lacking. The objective of this study was to elucidate whether use of an HFNC could reduce the arterial partial pressure of CO2 (PaCO2) in patients with acute hypercapnic respiratory failure who are receiving conventional oxygen (O2) therapy. METHODS: A propensity score-matched observational study was conducted to evaluate patients treated with an HFNC for acute hypercapnic respiratory failure from 2015 to 2016. The hypercapnia group was defined as patients with a PaCO2 >50 mm Hg and arterial pH <7.35. RESULTS: Eighteen patients in the hypercapnia group and 177 patients in the nonhypercapnia group were eligible for the present study. Eighteen patients in each group were matched by propensity score. Decreased PaCO2 and consequent pH normalization over time occurred in the hypercapnia group (P=0.002 and P=0.005, respectively). The initial PaCO2 level correlated linearly with PaCO2 removal after the use of an HFNC (R2=0.378, P=0.010). The fraction of inspired O2 used in the intensive care unit was consistently higher for 48 hours in the nonhypercapnia group. Physiological parameters such as respiratory rate and arterial partial pressure of O2 improved over time in both groups. CONCLUSIONS: Physiological parameters can improve after the use of an HFNC in patients with acute hypercapnic respiratory failure given low-flow O2 therapy via a facial mask. Further studies are needed to identify which hypercapnic patients might benefit from an HFNC.

Diagnostic and prognostic values of serum activin-a levels in patients with acute respiratory distress syndrome.

BACKGROUND: We aimed to evaluate whether serum activin-A levels are elevated and have any value in predicting severity and prognosis in acute respiratory distress syndrome (ARDS). METHODS: Retrospective cohort study was performed with patients who were admitted to MICU with diagnosis of ARDS and have serum samples stored within 48 h of Intensive care unit (ICU) admission between March 2013 and December 2016 at a single tertiary referral hospital. Serum activin-A levels were measured with ELISA kit, and were compared with those of normal healthy control and non-ARDS sepsis patients. RESULTS: Total 97 ARDS patients were included for the study. Levels of Activin-A were elevated in ARDS patients compared to those of healthy controls (Log-transformed activin-A levels 2.89 ± 0.36 vs. 2.34 ± 0.11, p < 0.001, absolute activin-A levels 1525.6 ± 1060.98 vs. 225.9 ± 30.1, p = 0.016) and non-ARDS sepsis patients (Log-transformed activin-A levels 2.89 ± 0.36 vs. 2.73 ± 0.34, p = 0.002, Absolute activin-A levels 1525.6 ± 1060.98 vs. 754.8 ± 123.5 pg/mL, p = 0.036). When excluding five outliers with extremely high activin-A levels, activin-A showed statistically significant correlation with in-hospital mortalities (In-hospital survivors 676.2 ± 407 vs. non-survivors 897.9 ± 561.9 pg/mL, p = 0.047). In predicting in-hospital mortality, serum activin-A concentrations showed superior area under curve compared to that of Acute physiologic and chronic health evaluation II scores (0.653; 95% CI [0541, 0.765] vs. 0.591, 95% CI [0.471, 0.710]). With cut-off level of 708 pg/mL, those with high serum activin-A levels had more than twofold increased risk of in-hospital mortalities. However, those relations were missing when outliers were in. CONCLUSIONS: Serum activin-A levels in ARDS patients are elevated. However, its levels are weakly associated with ARDS outcomes.

Nontuberculous mycobacterial pulmonary disease diagnosed by two methods: a prospective cohort study.

BACKGROUND: Microbiological criteria for diagnosing nontuberculous mycobacterial pulmonary disease (NTM-PD) include positive culture results from at least two separately expectorated sputum specimens or one bronchial washing or lavage. However, the clinical similarities and differences between patients diagnosed by these two methods remain unclear. We compared clinical features and prognoses of patients with NTM-PD diagnosed from both specimen types. METHODS: We analysed data from patients who participated in the Seoul National University Hospital NTM-PD cohort ( ClinicalTrials.gov identifier: NCT01616745). Baseline demographics, symptoms, radiographic findings, disease progression, and treatment responses were summarized and compared between patients diagnosed from sputum specimens and patients diagnosed from bronchoscopic specimens. RESULTS: Three hundred forty-seven patients were included in the analyses. Of these, 279 (80.4%) were diagnosed from two separately expectorated sputum specimens, and 68 (19.6%) were diagnosed from bronchoscopic specimens. Patients diagnosed from sputum specimens had more frequent and severe cough, sputum, postnasal drip, and high St. George's Respiratory Questionnaire scores. However, the extent and severity of the radiographic lesions, disease progression, and treatment responses were similar for both groups. Further analysis based on the following three groups (sputum culture positive, sputum culture negative/bronchoscopy, and scanty sputum/bronchoscopy groups) suggested that the scanty sputum/bronchoscopy group appeared to have the worst prognosis in terms of both time to progression and time to culture conversion. CONCLUSIONS: Although some symptoms and quality of life were worse in patients with NTM-PD diagnosed from sputum specimens, their prognoses were similar to those of patients diagnosed by bronchoscopic specimen. We recommend bronchoscopic sampling for patients in whom NTM-PD is suspected clinically or radiographically, especially those who have no or scanty sputum.

Serum Uric Acid Level as a Prognostic Marker in Patients With Acute Respiratory Distress Syndrome.

PURPOSE:: Uric acid acts as both a pathogenic inflammatory mediator and an antioxidative agent. Several studies have shown that uric acid level correlates with the incidence, severity, and prognosis of pulmonary diseases. However, the association between uric acid level and acute respiratory distress syndrome (ARDS) has not been studied. This study was conducted to elucidate how serum uric acid level is related with clinical prognosis of ARDS. METHODS:: A retrospective cohort study with propensity score matching was conducted at a medical intensive care unit of a tertiary teaching hospital. The medical records of patients diagnosed with ARDS admitted from 2005 through 2011 were reviewed. RESULTS:: Two hundred thirty-seven patients with ARDS met the inclusion criteria. Patients with a serum uric acid level <3.0 mg/dL were classified into the low uric acid group, and those with a level ≥3 mg/dL were classified into the normal to high uric acid group. We selected 40 patients in each group using propensity score matching. A higher percentage of patients in the low uric acid group experienced clinical improvement in ARDS. More patients died from sepsis in the normal to high uric acid group. Kaplan-Meier analysis showed that a low serum uric acid level was significantly associated with better survival rate. CONCLUSION:: In patients with ARDS, a low serum uric acid level may be a prognostic marker of a low risk of in-hospital mortality.

Respiratory virus of severe pneumonia in South Korea: Prevalence and clinical implications.

BACKGROUND: Severe viral pneumonia is associated with a high mortality rate. However, due to the vulnerability of critically ill patients, invasive diagnostic methods should be performed with caution in the intensive care unit (ICU). It would be helpful if the prevalence, risk factors, and clinical impact of virus detection are elucidated. METHODS: We evaluated patients with severe pneumonia between January 1st 2008 and December 31st 2015. Reverse transcription-polymerase chain reaction (RT-PCR) analysis was performed for 8 respiratory viruses when viral pathogen could not be excluded as the origin of severe pneumonia. The baseline characteristics, laboratory results, microbiological findings, and clinical outcomes of the patients were analyzed. RESULTS: Of the 2,347 patients admitted to the medical ICU, 515 underwent RT-PCR for respiratory viruses, 69 of whom had positive results. The detection rate was higher during the winter, with a community onset, in patients with history of recent chemotherapy, and low platelet count. Additional bronchoscopic sampling along with upper respiratory specimen increased the yield of viral detection. Respiratory syncytial virus was the most common pathogen detected, while influenza A was the most common virus with bacterial coinfection. Respiratory virus detection led to changes in clinical management in one-third of the patients. CONCLUSIONS: The detection of viral pathogens in patients with severe pneumonia is not rare, and can be more common in certain group of patients. Invasive sampling for RT-PCR can be helpful, and such detection can lead to positive changes in clinical management.

The effect of metformin on culture conversion in tuberculosis patients with diabetes mellitus.

BACKGROUND/AIMS: Patients with diabetes mellitus (DM) and tuberculosis (TB) have increased morbidity and a high risk of treatment failure or recurrence. It is important to manage both diseases simultaneously. Among anti-diabetic drugs, metformin inhibits intracellular growth of mycobacteria. Therefore, we examined the effects of metformin on TB treatment, especially in patients with DM. METHODS: This retrospective cohort study included patients with culture-positive pulmonary TB diagnosed between 2011 and 2012. The primary study outcome was sputum culture conversion after 2 months of treatment. RESULTS: Of 499 patients diagnosed with culture-positive pulmonary TB, 105 (21%) had DM at diagnosis. Among them, 62 (59.5%) were treated with metformin. Baseline characteristics, except for the presence of chronic renal disease, were not significantly different between the metformin and non-metformin groups. Metformin treatment had no significant effect on sputum culture conversion (p = 0.60) and recurrence within 1 year after TB treatment completion (p = 0.39). However, metformin improved the sputum culture conversion rate in patients with cavitary pulmonary TB, who have higher bacterial loads (odds ratio, 10.8; 95% confidence interval, 1.22 to 95.63). CONCLUSION: Among cavitary pulmonary TB patients with DM, metformin can be an effective adjunctive anti-TB agent to improve sputum culture conversion after 2 months of treatment.

Clinical Outcome of Eosinophilic Airway Inflammation in Chronic Airway Diseases Including Nonasthmatic Eosinophilic Bronchitis.

We enrolled patients with confirmed sputum eosinophilia who had visited our tertiary referral hospital between 2012 and 2015. We evaluated the incidence and predictors of exacerbations in patients with nonasthmatic eosinophilic bronchitis (NAEB), and investigated predictors of improvement in eosinophilic inflammation in chronic airway diseases with or without persistent airflow limitation. In total, 398 patients with sputum eosinophilia were enrolled. Of these, 152 (38.2%) had NAEB. The incidence rate of exacerbations requiring treatment with antibiotics, systemic corticosteroids, or hospital admission was 0.13 per patient-year (95% CI, 0.06-0.19) in NAEB. Inhaled corticosteroid (ICS) did not affect the risk of exacerbations, even in an analysis of propensity score. One hundred seventy-six patients had chronic airway diseases; in 37 of these (21.0%), sputum eosinophilia had improved at the 1-year follow-up. Patients who had persistent airflow limitation were less likely to show an improvement in eosinophilic inflammation (aOR, 0.26; 95% CI, 0.09-0.77) when they were treated with ICSs for less than 75% of the follow-up days. Exacerbations requiring systemic corticosteroids, antibiotics, or hospitalization did occur, although infrequently, in NAEB patients. Among patients with chronic airway diseases, those with persistent airflow limitation were less likely to show an improvement in eosinophilic airway inflammation.

Improved oxygenation 48 hours after high-flow nasal cannula oxygen therapy is associated with good outcome in immunocompromised patients with acute respiratory failure.

BACKGROUND: Respiratory failure requiring intubation is a risk factor for mortality in immunocompromised patients, therefore, noninvasive methods to avoid intubation are preferred in such patients. A high-flow nasal cannula (HFNC) is an alternative noninvasive technique for oxygen delivery but can be potentially harmful in cases of delayed intubation. We sought to identify the physiological predictors of outcome to assess the responsiveness to HFNC of immunocompromised patients with acute respiratory failure. METHODS: We retrospectively analyzed the medical records of immunocompromised patients treated with HFNC in 2015 and 2016 in a tertiary hospital. Oxygenation was assessed by calculating the SpO2/FiO2 (SF) ratio. Subjects were defined as "SF-improved" when HFNC resulted in an increase in the SF ratio compared with baseline. The values were collected at baseline, 12, 24, and 48 h. RESULTS: Ninety-one patients with a median age of 64 years were analyzed; 68.1% were men. There was no significant difference between the SF48-improved and the SF48-nonimproved groups in clinical baseline characteristics or severity of illness as evaluated at the time of initiation of HFNC by APACHE II, SAPS II, and SOFA. The 28-day mortality was significantly lower in the SF48-improved compared with the SF48-nonimproved group. In univariate analysis, mortality was significantly associated with body mass index (BMI), poor functional status, do-not-intubate (DNI) status, the "SF48-improved" group, the reason for immunocompromise, and the severity of illness at the time of initiation of HFNC. In multivariate analysis, "SF48-improved" group was not significantly associated with increased mortality [odds ratio (OR) 0.462; 95% confidence interval (CI), 0.107-1.988; P=0.299]. CONCLUSIONS: In immunocompromised patients with acute respiratory failure, an improved SF ratio 48 h after HFNC treatment was associated with improved 28-day mortality.

Histopathologic heterogeneity of acute respiratory distress syndrome revealed by surgical lung biopsy and its clinical implications.

BACKGROUND/AIMS: Diffuse alveolar damage (DAD) is the histopathologic hallmark of acute respiratory distress syndrome (ARDS). However, there are several non-DAD conditions mimicking ARDS. The purpose of this study was to investigate the histopathologic heterogeneity of ARDS revealed by surgical lung biopsy and its clinical relevance. METHODS: We retrospectively analyzed 84 patients with ARDS who met the criteria of the Berlin definition and underwent surgical lung biopsy between January 2004 and December 2013 in three academic hospitals in Korea. We evaluated their histopathologic findings and compared the clinical outcomes. Additionally, the impact of surgical lung biopsy on therapeutic alterations was examined. RESULTS: The histopathologic findings were highly heterogeneous. Of 84 patients undergoing surgical lung biopsy, DAD was observed in 31 patients (36.9%), while 53 patients (63.1%) did not have DAD. Among the non-DAD patients, diffuse interstitial lung diseases and infections were the most frequent histopathologic findings in 19 and 17 patients, respectively. Although the mortality rate was slightly higher in DAD (71.0%) than in non-DAD (62.3%), the difference was not significant. Overall, the biopsy results led to treatment alterations in 40 patients (47.6%). Patients with non-DAD were more likely to change the treatment than those with DAD (58.5% vs. 29.0%), but there were no significant improvements regarding the mortality rate. CONCLUSIONS: The histopathologic findings of ARDS were highly heterogeneous and classic DAD was observed in one third of the patients who underwent surgical lung biopsy. Although therapeutic alterations were more common in patients with non-DAD-ARDS, there were no significant improvements in the mortality rate.

Utility of the National Lung Screening Trial Criteria for Estimation of Lung Cancer in the Korean Population.

PURPOSE: Screening forlung cancerin high-risk patients using theNational Lung Screening Trial (NLST) criteria resulted in a decreased lung cancer-related mortality rate. However, whether these criteria are applicable to the Korean has not been investigated thus far. Therefore, we estimated the utility of the NLST criteria as a screening tool for lung cancer in the Korean population. MATERIALS AND METHODS: The total number of newly diagnosed lung cancer cases in 2013 was obtained from the Korea National Statistical Office. The proportion of newly diagnosed lung cancer cases that met the NLST criteria was calculated via a retrospective cohort of a tertiary referral hospital. We estimated the nationwide proportion of patients who met the NLST criteria using the 5th Korea National Health and Nutrition Examination Survey conducted during 2010-2012 (KNHANES V). RESULTS: Using KNHANES V data, we found that approximately 6.92% of the general population of Korea would meet the NLST criteria. In the tertiary referral hospital, 29.6% of the 2,689 newly diagnosed lung cancer patients met the NLST criteria. In 2013, the total number of newly diagnosed lung cancer cases in Korea was 23,177. The estimated nationwide proportions of lung cancer patients who met and did not meet the NLST criteria were 0.37% and 0.06%, respectively, yielding a ratio of 5.78. CONCLUSION: The NLST criteria demonstrated sound clinical utility for lung cancer screening of high-risk patients in Korea.

Implication of species change of Nontuberculous Mycobacteria during or after treatment.

BACKGROUND: Co-existence or subsequent isolation of multiple nontuberculous mycobacteria (NTM) species in same patient has been reported. However, clinical significance of these observations is unclear. The aim of this study was to determine clinical implications of changes of NTM species during or after treatment in patients with NTM lung disease. METHODS: Patients with NTM lung disease, who experienced changes of NTM species during treatment or within 2 years of treatment completion between January 1, 2009 and December 31, 2015, were included in the analysis. Demographic, clinical, microbiological, and radiographic data were reviewed and analyzed. RESULTS: During the study period, 473 patients were newly diagnosed with NTM lung disease. Treatment was started in 164 patients (34.6%). Among these 164 patients, 16 experienced changes of NTM species during or within 2 years of treatment completion. Seven showed changes from M. avium complex (MAC) to M. abscessus subspecies abscessus (MAA) and five patients displayed changes from M. abscessus subspecies massiliense (MAM) to MAC. With isolation of new NTM species, 6 out of 7 patients with change from MAC to MAA reported worsening of symptoms, whereas none of the five patients with change from MAM to MAC reported worsening of symptoms. All MAA isolated during or after treatment for MAC lung diseases showed inducible resistance to clarithromycin. CONCLUSIONS: Change of NTM species may occur during or after treatment for NTM lung disease. Especially, changes from MAC to MAA is accompanied by symptomatic and radiographic worsening as well as inducible resistance to clarithromycin.

Effect of Preadmission Metformin Use on Clinical Outcome of Acute Respiratory Distress Syndrome among Critically Ill Patients with Diabetes.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is related to high mortality and morbidity. There are no proven therapeutic measures however, to improve the clinical course of ARDS, except using low tidal volume ventilation. Metformin is known to have pleiotropic effects including anti-inflammatory activity. We hypothesized that pre-admission metformin might alter the progress of ARDS among intensive care unit (ICU) patients with diabetes mellitus (DM). METHODS: We performed a retrospective cohort study from January 1, 2005, to April 30, 2005 of patients who were admitted to the medical ICU at Seoul National University Hospital because of ARDS, and reviewed ARDS patients with DM. Metformin use was defined as prescribed within 3-month pre-admission. RESULTS: Of 558 patients diagnosed with ARDS, 128 (23.3%) patients had diabetes and 33 patients were treated with metformin monotherapy or in combination with other antidiabetic medications. Demographic characteristics, cause of ARDS, and comorbid conditions (except chronic kidney disease) were not different between metformin users and nonusers. Several severity indexes of ARDS were similar in both groups. The 30-day mortality was 42.42% in metformin users and 55.32% in metformin nonusers. On multivariable regression analysis, use of metformin was not significantly related to a reduced 30-day mortality (adjusted ß-coefficient, -0.19; 95% confidence interval, -1.76 to 1.39; p=0.816). Propensity score-matched analyses showed similar results. CONCLUSION: Pre-admission metformin use was not associated with reduced 30-day mortality among ARDS patients with DM in our medical ICU.

Treatment Outcomes of Mycobacterium avium Complex Lung Disease: A Systematic Review and Meta-analysis.

Background: The advent of macrolides has led to therapeutic advances in the treatment of Mycobacterium avium complex lung disease (MAC-LD). The aim of this study was to elucidate the treatment outcomes of macrolide-containing regimens. Methods: We performed a systematic review and meta-analysis of published studies reporting treatment outcomes of macrolide-containing regimens for MAC-LD using the Medline, Embase, and Cochrane Library databases through 31 July 2016. The rates of treatment success, default from treatment, and adverse events of macrolide-containing regimens were assessed. Treatment success was defined as either 12 months of sustained culture negativity while on therapy or achievement of culture conversion and completion of the planned treatment without relapse. Results: In total, 16 studies involving 1462 patients were included. The rate of treatment success was 60.0% (95% confidence interval [CI], 55.1%-64.8%). The proportion of patients who defaulted from the treatment was 16.0% (95% CI, 12.3%-19.7%). When a thrice-weekly dosing schedule was available, the default rate was 12.0% (95% CI, 8.9%-15.0%). Adverse events necessitating treatment discontinuation or dosage modification of macrolides were observed in 6.4% of patients (95% CI, 3.2%-9.5%), and decreased auditory acuity was the most common adverse event. Conclusions: Treatment outcomes of macrolide-containing regimens are relatively poor in terms of both the treatment success and default rates. The default rate could be reduced if a thrice-weekly dosing schedule is available. Clinicians should be aware of decreased auditory function as the most common adverse event associated with macrolide-containing regimens.

The additional role of Xpert MTB/RIF in the diagnosis of intrathoracic tuberculous lymphadenitis.

BACKGROUND: Diagnosis of intrathoracic tuberculosis (TB) lymphadenitis remains a challenge because of difficulties in obtaining adequate tissue and the lack of a sensitive test. Recently, Xpert MTB/RIF assay is being used for rapid diagnosis of pulmonary TB, but it has not yet been widely validated in intrathoracic TB lymphadenitis. The aim of this study was to assess the additional role of Xpert MTB/RIF in diagnosing intrathoracic TB lymphadenitis using endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) specimen. METHODS: Consecutive patients who underwent Xpert MTB/RIF assay using EBUS-TBNA specimen from January 2012 and November 2013 at a tertiary referral hospital were recruited. Among them, the cases with malignant lymph nodes were excluded. RESULTS: Among 73 patients, 13 (17.8%) cases were diagnosed with intrathoracic TB lymphadenitis. In detail, 10 patients were diagnosed using conventional methods only (histology or AFB culture) and 3 patients were additionally diagnosed when adding Xpert MTB/RIF assay. The median time to diagnosis using Xpert MTB/RIF (1 day) was shorter than conventional methods (3 days for histology, 14 days for AFB culture). Rifampin resistance was not detected in any patients. CONCLUSION: In patients with enlarged intrathoracic lymph nodes and low suspicion of malignancy, combination of conventional diagnostic methods with Xpert MTB/RIF could lead to additional and rapid diagnosis of intrathoracic TB lymphadenitis.