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Clinical phenotypes of COPD: Results of a Japanese epidemiological survey
Author(s) -
TATSUMI Koichiro,
KASAHARA Yasunori,
KUROSU Katsushi,
TANABE Nobuhiro,
TAKIGUCHI Yuichi,
KURIYAMA Takayuki
Publication year - 2004
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/j.1440-1843.2004.00611.x
Subject(s) - medicine , copd , phenotype , airway , epidemiology , air trapping , disease , pathology , lung , surgery , biochemistry , chemistry , gene
Objective: The Global Initiative for Obstructive Lung Disease characterizes COPD as airflow limitation caused by parenchymal destruction and/or small airway disease. This report characterizes the clinical features of these two phenotypes of COPD in Japan. Methodology: COPD was diagnosed by spirometric airflow limitation (FEV 1 /FVC < 70%), and all subjects underwent chest CT scanning. Patients with diffuse low attenuation areas (LAA) on CT scan were categorized as the emphysema‐dominant phenotype; those with little LAA were categorized as the airway disease‐dominant phenotype. The two groups were compared to identify significant clinical or demographic differences. Results: Of the 1438 patients analysed, 1294 (90%) were classified as having an emphysema‐dominant phenotype and 144 (10%) as having an airway disease‐dominant phenotype. The airway disease‐dominant phenotype was: more common than the emphysema‐dominant phenotype in women (15% vs. 7%, P < 0.01) and in non‐smokers (6% vs. 2%, P < 0.05); was more commonly complicated by asthmatic features (35% vs. 21%, P < 0.01); and had higher IgE and eosinophil levels ( P < 0.05) and less lung function impairment. Conclusion: This analysis is the first to clinically define two phenotypes of COPD in a Japanese epidemiological survey. There appear to be striking differences as well as overlap between these two groups. Further research is warranted to determine the significance of COPD phenotypes.