Severe COPD cases from Korea, Poland, and USA have substantial differences in respiratory symptoms and other respiratory illnesses

• Published in: International journal of chronic obstructive pulmonary disease Vol. 12; pp. 3415 - 3423
• Main Authors: Kim, Woo Jin, Yim, Jae-Joon, Kim, Deog Kyeom, Lee, Myung Goo, Fuhlbrigge, Anne L, Sliwinski, Pawel, Hawrylkiewicz, Iwona, Wan, Emily S, Cho, Michael H, Silverman, Edwin K
• Format: Journal Article
• Language: English
• Published: New Zealand Dove Medical Press Limited 01.01.2017; Dove Medical Press Ltd; Dove Medical Press
• Subjects: Adult; Age; Aged; Air pollution; Asthma; Asthma - epidemiology; Asthma - physiopathology; Body mass index; Bronchitis; Bronchitis, Chronic - epidemiology; Bronchitis, Chronic - physiopathology; Care and treatment; Chi-Square Distribution; Chronic obstructive lung disease; Chronic obstructive pulmonary disease; Cigarettes; Complications and side effects; COPD; Councils; Cultural differences; Diagnosis; Dyspnea; Dyspnea - epidemiology; Dyspnea - physiopathology; Epidemiology; Female; Forced Expiratory Volume; Hospitals; Humans; Illnesses; Logistic Models; Lung - physiopathology; Lung diseases; Male; Medical research; Middle Aged; Mortality; Multivariate Analysis; Odds Ratio; Original Research; Pneumonia; Poland - epidemiology; Pulmonary Disease, Chronic Obstructive - diagnosis; Pulmonary Disease, Chronic Obstructive - epidemiology; Pulmonary Disease, Chronic Obstructive - physiopathology; Questionnaires; Republic of Korea - epidemiology; Respiration; Respiratory diseases; Respiratory Symptoms; Risk Factors; Severity of Illness Index; Smoking; Smoking - adverse effects; Smoking - epidemiology; Spirometry; Surveys and Questionnaires; Tuberculosis; Tuberculosis, Pulmonary - epidemiology; Tuberculosis, Pulmonary - physiopathology; United States - epidemiology; Variables; Vital Capacity; Poland; United States; South Korea; United States > US; epidemiology; respiratory symptoms; tuberculosis; COPD
• ISSN: 1178-2005; 1176-9106; 1178-2005
• DOI: 10.2147/COPD.S145908

Chronic obstructive pulmonary disease (COPD), characterized by irreversible airflow obstruction, is a major cause of morbidity and mortality worldwide. However, geographic differences in the clinical characteristics of severe COPD patients have not been widely studied. We recruited a total of 828 severe COPD cases from three continents. Subjects in Poland were enrolled by the Institute of Tuberculosis and Lung Diseases in Warsaw; subjects in Korea participated at several university hospitals in Korea; and subjects in USA were enrolled at two clinics affiliated with academic medical centers. All subjects were over the age of 30 with at least 10 pack-years of cigarette smoking history. Cases manifested severe to very severe airflow obstruction with post-bronchodilator forced expiratory volume in 1 second (FEV ) <50% predicted and FEV /forced vital capacity <0.7. All subjects completed a detailed questionnaire and underwent standardized pre-bronchodilator and post-bronchodilator spirometry. Subjects with known tuberculosis (TB)-associated lung parenchymal destruction were excluded. Univariate and multivariate assessments of the impact of the country of origin on respiratory symptoms and respiratory illness were performed. In both univariate and multivariate analyses, a history of TB (38.7%) and physician-diagnosed asthma (43.9%) were significantly more common in subjects with severe COPD from Korea than USA or Poland, while attacks of bronchitis (64.2%) were more common in subjects with severe COPD from Poland. COPD subjects from Poland had more severe dyspnea (modified Medical Research Council 3.3±1.0) and more frequently reported symptoms of chronic bronchitis (52.2%). A history of TB was also more common in Poland (10.8%) than in USA (0.3%) severe COPD patients. Respiratory symptoms and other respiratory illnesses associated with severe COPD differed widely among three continents.