Chronic obstructive pulmonary disease (COPD) is a chronic airway inflammation characterized by fixed airflow limitation and chronic respiratory symptoms, such as cough, sputum, and dyspnea. COPD is a progressive disease characterized by a decline in lung function. During the natural course of the disease, acute deterioration of symptoms leading to hospital visits can occur and influence further disease progression and subsequent exacerbation. Moreover, COPD is not only restricted to pulmonary manifestations but can present with other systemic diseases as comorbidities or systemic manifestations, including lung cancer, cardiovascular disease, pulmonary hypertension, sarcopenia, and metabolic abnormalities. These pulmonary and extrapulmonary conditions lead to the aggravation of dyspnea, physical inactivity, decreased exercise capacity, functional decline, reduced quality of life, and increased mortality. In addition, pneumonia, which is attributed to both COPD itself and an adverse effect of treatment (especially the use of inhaled and/or systemic steroids), can occur and lead to further deterioration in the prognosis of COPD. This review summarizes the long-term outcomes of patients with COPD. In addition, recent studies on the prediction of adverse outcomes are summarized in the last part of the review.

Background and objective: Aside from smoking, which is already recognized as a strong risk factor for COPD, interest in the impact of particulate matter (PM) on COPD is increasing. This study aimed to investigate the effect of PM, especially with an aerodynamic diameter ≤2.5 µm (PM_2.5), and its chemical constituents on the exacerbation of COPD. Methods: Data on hospital visits including admission and outpatient clinic visits for exacerbation of COPD in Chuncheon, Korea, between 2006 and 2012 were extracted from the National Health Insurance Service database. PM_2.5 and its chemical constituents were measured on the roof of the four-story Kangwon National University Natural Sciences building once every 3 days. Meteorological data were provided by the Korean Meteorological Administration. Results: During the study period, the mean level of PM_2.5 was 35.0±25.2 µg/m³, and the number of daily hospital visits were 6.42±4.28 and 2.07±1.93 for males and females, respectively. The number of COPD-related hospital visits increased with increasing PM_2.5 after adjusting for meteorological covariates and females tended to be more affected sooner than males. Among the PM_2.5 constituents, Al, Si, and elemental carbon were associated with increased hospital visits and there was a difference according to sex. In males, some constituents of PM_2.5 were related to an increased risk of a hospital visit, mainly on the first and second days of measurement (Lag1 and Lag2). In contrast, there was no significant increase in the risk of hospital visits due to any of the PM_2.5 constituents in females. Conclusion: Concentrations of PM_2.5 mass and some of the PM_2.5 constituents were associated with increased COPD-related hospital visits in Chuncheon.

Background and objective: Guidelines recommend the use of simple but comprehensive tools such as COPD Assessment Test (CAT) and Clinical COPD Questionnaire (CCQ) to assess health status in COPD patients. We aimed to compare the ability of CAT and CCQ to predict exacerbation in COPD patients. Methods: We organized a multicenter prospective cohort study that included COPD patients. The relationships between CAT, CCQ, and other clinical measurements were analyzed by correlation analysis, and the impact of CAT and CCQ scores on exacerbation was analyzed by logistic regression analyses and receiver operating characteristic curve. Results: Among 121 COPD patients, CAT and CCQ score correlated with other symptom measures, lung function and exercise capacity as well. Compared with patients who did not experience exacerbation, those who experienced exacerbation (n=45; 38.2%) exhibited more severe airflow limitation, were more likely to have a history of exacerbation in the year prior to enrollment, and demonstrated higher CAT scores. CCQ scores were not significantly associated with exacerbations. A CAT score of ≥15 was an independent risk factor for exacerbation (adjusted odds ratio [aOR], 2.40; 95% CI, 1.03–6.50; P=0.04). Furthermore, CAT scores of ≥15 demonstrated an increased predictive ability for exacerbation compared with currently accepted guidelines for the use of CAT (≥10) and CCQ (≥1) in the assessment of COPD patients (area under the curve for CAT ≥15, CAT ≥10, and CCQ ≥1 was 0.61±0.04, 0.53±0.03, and 0.50±0.03, respectively; P=0.03). Conclusion: A CAT score of ≥15 indicates increased risk of exacerbation in COPD patients, whereas there is no evidence for increased risk based on CCQ score.

Background and objective: There are limited data on pulmonary arterial hypertension (PAH) in patients with tuberculosis-destroyed lung (TDL), a sequela of pulmonary tuberculosis. We identified the risk factors for PAH and their effects on acute exacerbation and mortality in patients with TDL, as well as the clinical differences in patients with chronic obstructive pulmonary disease (COPD) and PAH. Methods: A retrospective cohort study was conducted from 2010 through 2015 in a municipal referral hospital in South Korea. PAH was defined when echocardiographic pulmonary arterial pressure (PAP) was >40 mmHg. The clinical features and course of TDL patients with or without PAH were evaluated and differences between patients with COPD and PAH were analyzed. Results: Among the 195 patients with TDL, echocardiographic data were available in 53 patients, and their mean PAP was 50.72±23.99 mmHg. The PAH group (n=37) had a smaller lung volume (forced vital capacity % predicted, 51.55% vs 72.37%, P<0.001) and more extensively destroyed lungs (3.27 lobes vs 2 lobes, P<0.001) than those in the non-PAH group (n=16). A higher PAP was significantly correlated with a higher frequency of acute exacerbation (r=0.32, P=0.02). Multivariate analyses did not reveal any significant risk factors contributing to PAH in patients with TDL. Compared to COPD patients with PAH, TDL patients with PAH have smaller lung volume but a less severe airflow limitation. Tricuspid regurgitation and a D-shaped left ventricle during diastole were more frequently observed in TDL patients. The risk of exacerbation was not different between patients with PAH in COPD and TDL. Conclusion: PAH in patients with TDL was associated with severity of lung destruction but risk of exacerbation and mortality did not significantly differ between patients with PAH and without PAH.

Background and objective: Although depression is considered one of the comorbidities of COPD, the clinical characteristics of depression in patients with early COPD remain unknown. We aimed to use national-level data to identify the clinical features and risk factors of depression in patients with early COPD. Methods: We examined 7,550 subjects who were registered in the Korean National Health and Nutrition Examination Survey database of 2014 because that was the only year in which the Patient Health Questionnaire-9 for depression status was administered. Spirometry was used to identify patients with COPD whose forced expiratory volume in 1 second was 50% or more, and these patients were included in the analysis. Results: Of the 211 subjects with early COPD, 14.2% also had depression, whereas 85.8% did not. The patients with depression were predominantly living alone and had a greater prevalence of diabetes compared with the patients without depression. The overall quality of life of the subjects with depression was lower than that of those without depression, and only the quality of life index correlated significantly with depression severity. In the multivariate regression analysis, female sex (adjusted OR, 1.79; 95% CI, 1.38–2.31; p<0.01), living alone (adjusted OR, 1.86; 95% CI, 1.37–2.51; p<0.01), and low income (adjusted OR, 2.17; 95% CI, 1.55–3.04; p<0.01) were identified as significant risk factors for depression. Conclusion: In patients with early COPD, depression was associated with a low quality of life, and female sex, living alone and low income were significant risk factors for depression.

Mediastinal lymph node (LN) staging in individuals with non-small-cell lung cancer plays an important role in staging and treatment planning. This study aimed to assess the accuracy of computed tomography (CT) texture analysis (CTTA) in differentiating benign and malignant mediastinal LNs. Pathologically confirmed malignant and benign mediastinal LN samples, obtained using endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), were retrospectively reviewed, in addition to chest CT and 18-fluorodeoxyglucose (FDG) uptake positron emission tomography (PET) data. For each LN, CTTA was performed using “AVIEW” software (Coreline Soft, Republic of Korea) by drawing a region of interest. A total of 132 LNs from 80 patients were included and classified into two groups according to pathology results: malignant (n = 61) and benign (n = 71). In EBUS, size > 1 cm, round shape, heterogeneous echogenicity, and presence of coagulation necrosis sign were more prevalent in malignant than in benign LNs; length was the only feature that distinguished the two groups. Among CTTA features, compactness and normalized standard deviation (SD) showed differences between the two groups. The ability to distinguish malignant LNs was higher using high standard uptake value (SUV) on FDG PET/CT (SUVmax ≥ 5) and normalized SD on CTTA (area under the receiver operating characteristic curve 0.739 versus 0.742, respectively); however, normalized SD demonstrated very low sensitivity despite high specificity. CTTA may be helpful in distinguishing between benign and malignant LNs; however, the diagnostic value was not high. Therefore, integrated evaluation with other imaging modalities is needed.