title: Identification of five chronic obstructive pulmonary disease subgroups with different prognoses in the ECLIPSE cohort using cluster analysis.
abstract: BACKGROUND
  Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease that likely includes clinically relevant subgroups.
  
  
  OBJECTIVE
  To identify subgroups of COPD in ECLIPSE (Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints) subjects using cluster analysis and to assess clinically meaningful outcomes of the clusters during 3 years of longitudinal follow-up.
  
  
  METHODS
  Factor analysis was used to reduce 41 variables determined at recruitment in 2,164 patients with COPD to 13 main factors, and the variables with the highest loading were used for cluster analysis. Clusters were evaluated for their relationship with clinically meaningful outcomes during 3 years of follow-up. The relationships among clinical parameters were evaluated within clusters.
  
  
  RESULTS
  Five subgroups were distinguished using cross-sectional clinical features. These groups differed regarding outcomes. Cluster A included patients with milder disease and had fewer deaths and hospitalizations. Cluster B had less systemic inflammation at baseline but had notable changes in health status and emphysema extent. Cluster C had many comorbidities, evidence of systemic inflammation, and the highest mortality. Cluster D had low FEV1, severe emphysema, and the highest exacerbation and COPD hospitalization rate. Cluster E was intermediate for most variables and may represent a mixed group that includes further clusters. The relationships among clinical variables within clusters differed from that in the entire COPD population.
  
  
  CONCLUSIONS
  Cluster analysis using baseline data in ECLIPSE identified five COPD subgroups that differ in outcomes and inflammatory biomarkers and show different relationships between clinical parameters, suggesting the clusters represent clinically and biologically different subtypes of COPD.
authors: 1 Pulmonary and Critical Care Medicine, University of Nebraska Medical Center, Omaha, Nebraska.
authors: Stephen I
authors: SI
authors: Rennard
authors: Nicholas
authors: N
authors: Locantore
authors: Bruno
authors: B
authors: Delafont
authors: Ruth
authors: R
authors: Tal-Singer
authors: Edwin K
authors: EK
authors: Silverman
authors: Jørgen
authors: J
authors: Vestbo
authors: Bruce E
authors: BE
authors: Miller
authors: Per
authors: P
authors: Bakke
authors: Bartolomé
authors: B
authors: Celli
authors: Peter M A
authors: PM
authors: Calverley
authors: Harvey
authors: H
authors: Coxson
authors: Courtney
authors: C
authors: Crim
authors: Lisa D
authors: LD
authors: Edwards
authors: David A
authors: DA
authors: Lomas
authors: William
authors: W
authors: MacNee
authors: Emiel F M
authors: EF
authors: Wouters
authors: Julie C
authors: JC
authors: Yates
authors: Ignacio
authors: I
authors: Coca
authors: Alvar
authors: A
authors: Agustí
mesh_terms: D016000:Cluster Analysis; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000145:classification* / Q000175:diagnosis / Q000503:physiopathology; D013997:Time Factors
keywords: chronic obstructive pulmonary disease; cluster analysis; longitudinal outcomes