Characterisation of COPD heterogeneity in the ECLIPSE cohort
1 Thorax Institute, Hospital Clinic, IDIBAPS, Universitat de Barcelona; CIBER Enfermedades Respiratorias and Fundació Caubet-Cimera, Mallorca, Spain
2 Department of Respiratory Medicine; University Hospital Aintree, Liverpool, UK
3 Department of Respiratory Medicine; Brigham and Women's Hospital, Boston, MA, USA
4 Department of Radiology, University of British Columbia, Vancouver General Hospital, Vancouver, BC, Canada
5 GlaxoSmithKline, Research Triangle Park, NC, USA
6 Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Cambridge, UK
7 University of Edinburgh & Royal Infirmary, Edinburgh, UK
8 GlaxoSmithKline, King of Prussia, PA, USA
9 University of Nebraska Medical Center, Omaha, NE, USA
10 Department of Medicine; Brigham and Women's Hospital, Boston, MA, USA
11 Department of Respiratory Medicine, Maastricht University Medical Centre, Maastricht, the Netherlands
12 Department of Cardiology and Respiratory Medicine, Hvidovre Hospital/University of Copenhagen, Denmark, and University of Manchester, Manchester Academic Health Science Centre, UK
Respiratory Research 2010, 11:122 doi:10.1186/1465-9921-11-122Published: 10 September 2010
Chronic obstructive pulmonary disease (COPD) is a complex condition with pulmonary and extra-pulmonary manifestations. This study describes the heterogeneity of COPD in a large and well characterised and controlled COPD cohort (ECLIPSE).
We studied 2164 clinically stable COPD patients, 337 smokers with normal lung function and 245 never smokers. In these individuals, we measured clinical parameters, nutritional status, spirometry, exercise tolerance, and amount of emphysema by computed tomography.
COPD patients were slightly older than controls and had more pack years of smoking than smokers with normal lung function. Co-morbidities were more prevalent in COPD patients than in controls, and occurred to the same extent irrespective of the GOLD stage. The severity of airflow limitation in COPD patients was poorly related to the degree of breathlessness, health status, presence of co-morbidity, exercise capacity and number of exacerbations reported in the year before the study. The distribution of these variables within each GOLD stage was wide. Even in subjects with severe airflow obstruction, a substantial proportion did not report symptoms, exacerbations or exercise limitation. The amount of emphysema increased with GOLD severity. The prevalence of bronchiectasis was low (4%) but also increased with GOLD stage. Some gender differences were also identified.
The clinical manifestations of COPD are highly variable and the degree of airflow limitation does not capture the heterogeneity of the disease.