title: Comorbidities and risk of mortality in patients with chronic obstructive pulmonary disease.
abstract: BACKGROUND
  Patients with chronic obstructive pulmonary disease (COPD) are afflicted by comorbidities. Few studies have prospectively evaluated COPD comorbidities and mortality risk.
  
  
  OBJECTIVE
  To prospectively evaluate COPD comorbidities and mortality risk.
  
  
  METHODS
  We followed 1,664 patients with COPD in five centers for a median of 51 months. Systematically, 79 comorbidities were recorded. We calculated mortality risk using Cox proportional hazard, and developed a graphic representation of the prevalence and strength of association to mortality in the form of a "comorbidome". A COPD comorbidity index (COPD specific comorbidity test [COTE]) was constructed based on the comorbidities that increase mortality risk using a multivariate analysis. We tested the COTE index as predictor of mortality and explored whether the COTE index added predictive information when used with the validated BODE index.
  
  
  RESULTS
  Fifteen of 79 comorbidities differed in prevalence between survivors and nonsurvivors. Of those, 12 predicted mortality and were integrated into the COTE index. Increases in the COTE index were associated with an increased risk of death from COPD-related (hazard ratio [HR], 1.13; 95% confidence interval, 1.08-1.18; P < 0.001) and non-COPD-related causes (HR, 1.18; 95% confidence interval, 1.15-1.21; P < 0.001). Further, increases in the BODE and COTE were independently associated with increased risk of death. A COTE score of greater than or equal to 4 points increased by 2.2-fold the risk of death (HR, 2.26-2.68; P < 0.001) in all BODE quartile.
  
  
  CONCLUSIONS
  Comorbidities are frequent in COPD and 12 of them negatively influence survival. A simple disease-specific comorbidities index (COTE) helps assess mortality risk in patients with COPD.
authors.affiliation: Pulmonary and Critical Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. mdivo@partners.org
authors.forename: Miguel
authors.initials: M
authors.lastname: Divo
authors.forename: Claudia
authors.initials: C
authors.lastname: Cote
authors.forename: Juan P
authors.initials: JP
authors.lastname: de Torres
authors.forename: Ciro
authors.initials: C
authors.lastname: Casanova
authors.forename: Jose M
authors.initials: JM
authors.lastname: Marin
authors.forename: Victor
authors.initials: V
authors.lastname: Pinto-Plata
authors.forename: Javier
authors.initials: J
authors.lastname: Zulueta
authors.forename: Carlos
authors.initials: C
authors.lastname: Cabrera
authors.forename: Jorge
authors.initials: J
authors.lastname: Zagaceta
authors.forename: Gary
authors.initials: G
authors.lastname: Hunninghake
authors.forename: Bartolome
authors.initials: B
authors.lastname: Celli
mesh_terms: D000368:Aged; D015897:Comorbidity; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology / Q000401:mortality*; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D014481:United States / Q000453:epidemiology