title: The progression of chronic obstructive pulmonary disease is heterogeneous: the experience of the BODE cohort.
abstract: BACKGROUND
  Chronic obstructive pulmonary disease (COPD) is thought to result in rapid and progressive loss of lung function usually expressed as mean values for whole cohorts.
  
  
  OBJECTIVE
  Longitudinal studies evaluating individual lung function loss and other domains of COPD progression are needed.
  
  
  METHODS
  We evaluated 1,198 stable, well-characterized patients with COPD (1,100 males) recruited in two centers (Florida and Tenerife, Spain) and annually monitored their multidomain progression from 1997 to 2009. Patients were followed for a median of 64 months and up to 10 years. Their individual FEV(1) (L) and BODE index slopes, expressed as annual change, were evaluated using regression models for repeated measures. A total of 751 patients with at least three measurements were used for the analyses.
  
  
  RESULTS
  Eighteen percent of patients had a statistically significant FEV(1) slope decline (-86 ml/yr; 95% confidence interval [CI], -32 to -278 ml/yr). Higher baseline FEV(1) (relative risk, 1.857; 95% CI, 1.322-2.610; P < 0.001) and low body mass index (relative risk, 1.071; 95% CI, 1.035-1.106; P < 0.001) were independently associated with FEV(1) decline. The BODE index had a statistically significant increase (0.55, 0.20-1.37 point/yr) in only 14% of patients and these had more severe baseline obstruction. Concordance between FEV1 and BODE change was low (κ Cohen, 16%). Interestingly, 73% of patients had no significant slope change in FEV1 or BODE. Only the BODE change was associated with mortality in patients without FEV(1) progression.
  
  
  CONCLUSIONS
  The progression of COPD is very heterogeneous. Most patients show no statistically significant decline of FEV(1) or increase in BODE. The multidimensional evaluation of COPD should offer insight into response to COPD management.
authors.affiliation: Pulmonary Department, Hospital Universitario La Candelaria, Tenerife, Spain. casanovaciro@gmail.com
authors.forename: Ciro
authors.initials: C
authors.lastname: Casanova
authors.forename: Juan P
authors.initials: JP
authors.lastname: de Torres
authors.forename: Armando
authors.initials: A
authors.lastname: Aguirre-Jaíme
authors.forename: Victor
authors.initials: V
authors.lastname: Pinto-Plata
authors.forename: Jose M
authors.initials: JM
authors.lastname: Marin
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Cordoba
authors.forename: Rebeca
authors.initials: R
authors.lastname: Baz
authors.forename: Claudia
authors.initials: C
authors.lastname: Cote
authors.forename: Bartolome R
authors.initials: BR
authors.lastname: Celli
mesh_terms: D000368:Aged; D000465:Algorithms; D015992:Body Mass Index; D018450:Disease Progression; D017079:Exercise Tolerance; D005260:Female; D005431:Florida / Q000453:epidemiology; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000175:diagnosis / Q000401:mortality* / Q000503:physiopathology* / Q000628:therapy; D011788:Quality of Life; D012044:Regression Analysis; D012129:Respiratory Function Tests; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013030:Spain / Q000453:epidemiology; D015996:Survival Rate