title: Two distinct chronic obstructive pulmonary disease (COPD) phenotypes are associated with high risk of mortality.
abstract: BACKGROUND
  In COPD patients, mortality risk is influenced by age, severity of respiratory disease, and comorbidities. With an unbiased statistical approach we sought to identify clusters of COPD patients and to examine their mortality risk.
  
  
  METHODS
  Stable COPD subjects (n = 527) were classified using hierarchical cluster analysis of clinical, functional and imaging data. The relevance of this classification was validated using prospective follow-up of mortality.
  
  
  RESULTS
  The most relevant patient classification was that based on three clusters (phenotypes). Phenotype 1 included subjects at very low risk of mortality, who had mild respiratory disease and low rates of comorbidities. Phenotype 2 and 3 were at high risk of mortality. Phenotype 2 included younger subjects with severe airflow limitation, emphysema and hyperinflation, low body mass index, and low rates of cardiovascular comorbidities. Phenotype 3 included older subjects with less severe respiratory disease, but higher rates of obesity and cardiovascular comorbidities. Mortality was associated with the severity of airflow limitation in Phenotype 2 but not in Phenotype 3 subjects, and subjects in Phenotype 2 died at younger age.
  
  
  CONCLUSIONS
  We identified three COPD phenotypes, including two phenotypes with high risk of mortality. Subjects within these phenotypes may require different therapeutic interventions to improve their outcome.
authors.affiliation: Service de Pneumologie, Hôpital Cochin, AP-HP and Université Paris Descartes, Sorbonne Paris Cité, Paris, France. pierre-regis.burgel@cch.aphp.fr
authors.forename: Pierre-Régis
authors.initials: PR
authors.lastname: Burgel
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Paillasseur
authors.forename: Bernard
authors.initials: B
authors.lastname: Peene
authors.forename: Daniel
authors.initials: D
authors.lastname: Dusser
authors.forename: Nicolas
authors.initials: N
authors.lastname: Roche
authors.forename: Johan
authors.initials: J
authors.lastname: Coolen
authors.forename: Thierry
authors.initials: T
authors.lastname: Troosters
authors.forename: Marc
authors.initials: M
authors.lastname: Decramer
authors.forename: Wim
authors.initials: W
authors.lastname: Janssens
mesh_terms: D000367:Age Factors; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011379:Prognosis; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000145:classification* / Q000235:genetics / Q000401:mortality*; D012307:Risk Factors; D015996:Survival Rate