Community-acquired pneumonia is common and important infectious disease in adults. This work represents an update to 2009 treatment guideline for community-acquired pneumonia in Korea. The present clinical practice guideline provides revised recommendations on the appropriate diagnosis, treatment, and prevention of community-acquired pneumonia in adults aged 19 years or older, taking into account the current situation regarding community-acquired pneumonia in Korea. This guideline may help reduce the difference in the level of treatment between medical institutions and medical staff, and enable efficient treatment. It may also reduce antibiotic resistance by preventing antibiotic misuse against acute lower respiratory tract infection in Korea.

IntroductionParticulate matter and air pollution in Korea are becoming worse. There is a lack of research regarding the impact of particulate matter on patients with COPD. Therefore, the purpose of this study was to investigate the effects of various air pollution factors, including particulate matter, on the incidence rate of severe acute exacerbations of COPD (AECOPD) events.MethodsWe analyzed the relationship between air pollutants and AECOPD events that required hospitalization at Guro Hospital in Korea from January 1, 2015 to May 31, 2017. We used general linear models with Poisson distribution and log-transformation to obtain adjusted relative risk (RR). We conducted further analysis through the Comprehensive Air-quality Index (CAI) that is used in Korea.ResultsAmong various other air pollutants, particulate matter was identified as a major source of air pollution in Korea. When the CAI score was over 50, the incidence rate of severe AECOPD events was statistically significantly higher [RR 1.612, 95% CI, 1.065–2.440, P=0.024]. Additionally, the particulate matter levels 3 days before hospitalization were statistically significant [RR 1.003, 95% CI, 1.001–1.005, P=0.006].ConclusionParticulate matter and air pollution increase the incidence rate of severe AECOPD events. COPD patients should be cautioned against outdoor activities when particulate matter levels are high.

Background/AimsPulmonary sarcomatoid carcinoma (PSC) is a poorly differentiated non-small cell lung cancer (NSCLC) that contains components of spindle or giant cells. Owing to its low prevalence, there are insufficient data regarding its clinical features, therapeutic strategies and prognosis.MethodsThe medical records of 26 patients diagnosed with PSC from January 2009 to June 2015 were reviewed and analyzed for clinicopathological characteristics, treatment modality, and outcomes.ResultsThe median age was 69.5 years. Twenty-three patients (88%) were male. Twenty-four patients (92%) were smokers. The median time from symptom onset to diagnosis was one month. Eighteen patients (69%) were diagnosed at an advanced stage. Pleomorphic carcinoma was the most common subtype, and epidermal growth factor receptor (EGFR) mutation was positive in two of 11 patients. Among 13 patients tested for programmed death ligand 1 (PD-L1) immunohistochemistry assay, eight showed high expression of PD-L1. The median overall survival (OS) of all patients was 9.5 months. In total, 12 patients were treated with chemotherapy: nine with platinum-based doublet therapy, two with tyrosine kinase inhibitor, and one with docetaxel. Seven patients showed partial response or stable disease. The median OS and progression-free survival of patients who received chemotherapy were 8.7 and 2.8 months, respectively.ConclusionsPSC was more common in males, smokers, and the elderly, with worse prognosis than ordinary NSCLC; chemotherapy response was favorable, and EGFR mutation status and PD-L1 expression may offer more therapeutic options.

PurposeThe most common cause of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is respiratory infection. Most studies of bacterial or viral cause in AECOPD have been conducted in Western countries. We investigated bacterial and viral identification rates in AECOPD in Korea.Materials and MethodsWe reviewed and analyzed medical records of 736 cases of AECOPD at the Korea University Guro Hospital. We analyzed bacterial and viral identification rates and classified infections according to epidemiological factors, such as Global Initiative for Chronic Obstructive Lung Disease stage, mortality, and seasonal variation.ResultsThe numbers of AECOPD events involving only bacterial identification, only viral identification, bacterial-viral co-identification, and no identification were 200 (27.2%), 159 (21.6%), 107 (14.5%), and 270 (36.7%), respectively. The most common infectious bacteria identified were Pseudomonas aeruginosa (13.0%), Streptococcus pneumoniae (11.4%), and Haemophilus influenzae (5.3%); the most common viruses identified were influenza virus (12.4%), rhinovirus (9.4%), parainfluenza virus (5.2%), and metapneumovirus (4.9%). The bacterial identification rate tended to be higher at more advanced stages of chronic obstructive pulmonary disease (p=0.020 overall, p=0.011 for P. aeruginosa, p=0.048 for S. pneumoniae). Staphylococcus aureus and Klebsiella pneumoniae were identified more in mortality group (p=0.003 for S. aureus, p=0.009 for K. pneumoniae). All viruses were seasonal (i.e., greater prevalence in a particular season; p<0.050). Influenza virus and rhinovirus were mainly identified in the winter, parainfluenza virus in the summer, and metapneumovirus in the spring.ConclusionThis information on the epidemiology of respiratory infections in AECOPD will improve the management of AECOPD using antibiotics and other treatments in Korea.

The wide variability of isoniazid (INH) pharmacokinetics is mainly attributed to the trimodal N‐acetyltransferase 2 (NAT2) acetylator phenotype, that is, rapid, intermediate, and slow. Consequently, a uniform INH dose in current clinical practice may lead to treatment failure and emergence of drug resistance. There is a lack of studies on specific doses of INH for different NAT2 acetylator phenotypes among tuberculosis (TB) patients. Therefore, we aimed to provide insight into the optimal dosing of INH for each NAT2 acetylator phenotype with respect to the probability of achieving a pharmacokinetic (PK)/pharmacodynamic target. PK, the NAT2 genotype, and clinical data were collected in a multicenter prospective cohort study conducted at 13 clinical centers in Korea. Population PK modeling and simulation were carried out. Data from 454 TB patients were divided into a training data set and a test data set at a ratio of 4 to 1. The PK of the training data were best described by a 2‐compartment model with allometric scaling for body size effect. Importantly, NAT2 acetylator phenotypes significantly affected the apparent clearance. Our model, which provided better predictive performance compared with previously published models, was evaluated by external validation using the test set. The simulation for assessing target efficacy and toxicity indicated that the best INH dosing regimens for Korean tuberculosis patients were once‐daily doses of 400, 300, and 200 mg for rapid, intermediate, and slow acetylators, respectively. In conclusion, our study provides a step forward in precision dosing for antituberculosis management.

IntroductionAcute exacerbation of COPD (AECOPD) leads to rapid deterioration of pulmonary function and quality of life. It is unclear whether the prognosis for AECOPD differs depending on the bacterium or virus identified. The purpose of this study is to determine whether readmission of patients with severe AECOPD varies according to the bacterium or virus identified.MethodsWe performed a retrospective review of medical records of 704 severe AECOPD events at Korea University Guro Hospital from January 2011 to May 2017. We divided events into two groups, one in which patients were readmitted within 30 days after discharge and the other in which there was no readmission.ResultsOf the 704 events, 65 were followed by readmission within 30 days. Before propensity score matching, the readmission group showed a higher rate of bacterial identification with no viral identification and a higher rate of identification with the Pseudomonas aeruginosa (P=0.003 and P=0.007, respectively). Using propensity score matching, the readmission group still showed a higher P. aeruginosa identification rate (P=0.030), but there was no significant difference in the rate of bacterial identification, with no viral identification (P=0.210). In multivariate analysis, the readmission group showed a higher P. aeruginosa identification rate than the no-readmission group (odds ratio, 4.749; 95% confidence interval, 1.296–17.041; P=0.019).ConclusionP. aeruginosa identification is associated with a higher readmission rate in AECOPD patients.

Introduction: The use of antibiotics is based on the clinician’s experience and judgment, and antibiotics may often be overused in the treatment of acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Eosinophils have been studied as biomarkers of bacterial infection and prognostic factors in chronic obstructive pulmonary disease and AECOPD. Thus, the purpose of this study was to determine whether eosinophils could be used to determine bacterial infection in AECOPD events. Methods: We retrospectively analyzed the medical records of patients admitted to Korea University Guro Hospital for AECOPD between January 2011 and May 2017. Data pertaining to baseline characteristics, results of previous pulmonary function tests, treatment information during the admission period, and history of pulmonary treatment were collected before admission. Results: A total of 736 AECOPD events were eligible for inclusion and were divided into two groups based on the eosinophil count: those involving eosinophil counts of less than 2% (546 events) and those involving counts of 2% or more (190 events). In univariate analysis, the only bacterial pathogen identification events and bacterial-viral pathogen co-identification events were significantly more frequent in the group with eosinophil counts of less than 2% ( P =0.010 and P =0.001, respectively). In logistic regression analysis, the rates of only bacterial pathogen identification [odds ratios =1.744; 95% confidence interval, 1.107–2.749; P =0.017] and bacterial-viral pathogen co-identification [odds ratios=2.075; 95% confidence interval, 1.081–3.984; P =0.028] were higher in the group with eosinophil count less than 2%. Conclusion: In conclusion, eosinophil counts of less than 2% are potential indicators of a bacterial infection in AECOPD events. Eosinophils could thus serve as a reference for the use of antibiotics in AECOPD treatment.

Background: The national Public-Private Mix (PPM) tuberculosis (TB) control project provides for the comprehensive management of TB patients at private hospitals in South Korea. Surveillance and monitoring of TB under the PPM project are essential toward achieving TB elimination goals. Methods: TB is a nationally notifiable disease in South Korea and is monitored using the surveillance system. The Korea Centers for Disease Control and Prevention quarterly generates monitoring indicators for TB management, used to evaluate activities of the PPM hospitals by the central steering committee of the national PPM TB control project. Based on the notification date, TB patients at PPM hospitals were enrolled in each quarter, forming a cohort, and followed up for at least 12 months to identify treatment outcomes. This report analyzed the dataset of cohorts the first quarter of 2016 through the fourth quarter of 2017. Results: The coverage of sputum, smear, and culture tests among the pulmonary TB cases were 92.8% and 91.5%, respectively. The percentage of positive sputum smear and culture test results were 30.7% and 61.5%, respectively. The coverage of drug susceptibility tests among the culture-confirmed cases was 92.8%. The treatment success rate among the smear-positive drug-susceptible cases was 83.2%. The coverage of latent TB infection treatment among the childhood TB contacts was significantly higher than that among the adult contacts (85.6% vs. 56.0%, p=0.001). Conclusion: This is the first official report to analyze monitoring indicators, describing the current status of the national PPM TB control project. To sustain its effect, strengthening the monitoring and evaluation systems is essential.