title: Large-scale international validation of the ADO index in subjects with COPD: an individual subject data analysis of 10 cohorts.
abstract: BACKGROUND
  Little evidence on the validity of simple and widely applicable tools to predict mortality in patients with chronic obstructive pulmonary disease (COPD) exists.
  
  
  OBJECTIVE
  To conduct a large international study to validate the ADO index that uses age, dyspnoea and FEV(1) to predict 3-year mortality and to update it in order to make prediction of mortality in COPD patients as generalisable as possible.
  
  
  METHODS
  Individual subject data analysis of 10 European and American cohorts (n=13 914).
  
  
  METHODS
  Population-based, primary, secondary and tertiary care.
  
  
  METHODS
  COPD GOLD stages I-IV.
  
  
  METHODS
  We validated the original ADO index. We then obtained an updated ADO index in half of our cohorts to improve its predictive accuracy, which in turn was validated comprehensively in the remaining cohorts using discrimination, calibration and decision curve analysis and a number of sensitivity analyses.
  
  
  RESULTS
  1350 (9.7%) of all subjects with COPD (60% male, mean age 61 years, mean FEV(1) 66% predicted) had died at 3 years. The original ADO index showed high discrimination but poor calibration (p<0.001 for difference between predicted and observed risk). The updated ADO index (scores from 0 to 14) preserved excellent discrimination (area under curve 0.81, 95% CI 0.80 to 0.82) but showed much improved calibration with predicted 3-year risks from 0.7% (95% CI 0.6% to 0.9%, score of 0) to 64.5% (61.2% to 67.7%, score of 14). The ADO index showed higher net benefit in subjects at low-to-moderate risk of 3-year mortality than FEV(1) alone.
  
  
  CONCLUSIONS
  The updated 15-point ADO index accurately predicts 3-year mortality across the COPD severity spectrum and can be used to inform patients about their prognosis, clinical trial study design or benefit harm assessment of medical interventions.
authors.affiliation: Department of Epidemiology,  Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland,  USA.
authors.forename: Milo A
authors.initials: MA
authors.lastname: Puhan
authors.forename: Nadia N
authors.initials: NN
authors.lastname: Hansel
authors.forename: Patricia
authors.initials: P
authors.lastname: Sobradillo
authors.forename: Paul
authors.initials: P
authors.lastname: Enright
authors.forename: Peter
authors.initials: P
authors.lastname: Lange
authors.forename: Demarc
authors.initials: D
authors.lastname: Hickson
authors.forename: Ana M
authors.initials: AM
authors.lastname: Menezes
authors.forename: Gerben
authors.initials: G
authors.lastname: ter Riet
authors.forename: Ulrike
authors.initials: U
authors.lastname: Held
authors.forename: Antonia
authors.initials: A
authors.lastname: Domingo-Salvany
authors.forename: Zab
authors.initials: Z
authors.lastname: Mosenifar
authors.forename: Josep M
authors.initials: JM
authors.lastname: Antó
authors.forename: Karel G M
authors.initials: KG
authors.lastname: Moons
authors.forename: Alphons
authors.initials: A
authors.lastname: Kessels
authors.forename: Judith
authors.initials: J
authors.lastname: Garcia-Aymerich