The Identification of Phenotypes in Patients With Severe Chronic Obstructive Pulmonary Disease (Groningen Severe COPD Cohort)

Rationale: Chronic Obstructive Pulmonary Disease (COPD) is defined by airway obstruction. However, the degree of airflow limitation does not adequately describe the complexity of COPD because significant heterogeneity exists between patients with respect to their clinical presentation, physiology, imaging, response to therapy, decline in lung function and survival. Currently, a clear alternative for describing COPD does not exist but the identification of subgroups of COPD patients based on clinical or genomic and epigenomic factors (phenotypes) could be useful. The continuous flow of very severe COPD patients to the UMCG gives the investigators the unique opportunity to perform a study on the phenotypes of very severe COPD and the underlying gene-environment interaction. The investigators anticipate that the findings of this study will lead to an earlier identification of those subjects who are at risk to develop severe or very severe COPD. In addition, it will lead to a better clinical characterisation of established COPD, possibly enabling a more tailored treatment of different COPD subphenotypes. Objectives: Primary Objective: To identify new clinical phenotypes in patients with severe chronic obstructive pulmonary disease (COPD) using a cluster analysis. Secondary Objectives: To: * identify clinical phenotypes (based on e.g. lung function, clinical, radiologic, systemic, pathological and immunological parameters) in patients with severe COPD. * identify endotypes/ intermediate phenotypes in patients with severe COPD. * investigate the contribution of (epi)genomics (including genetics and gene expression) to characterize patients with subsets of severe COPD. Study design: Observational cross-sectional study with a 2 phase design Study population: Patients with severe COPD who are referred to the UMCG for a consultation on lung transplantation or bronchoscopic lung volume reduction.