title: Identifying COPD patients at increased risk of mortality: predictive value of clinical study baseline data.
abstract: BACKGROUND
  Identifying chronic obstructive pulmonary disease (COPD) patients at increased risk of mortality is an important component of effective disease management.
  
  
  METHODS
  A pooled analysis of patients with severe COPD, from two well-controlled 1-year studies, was conducted using Cox regression and spline analysis to evaluate predictability of baseline demographic data and in-study variables for mortality risk, and to evaluate the effect of treatment allocation to budesonide and formoterol, versus their respective control groups, on these outcomes.
  
  
  RESULTS
  In the pooled analysis, a Cox regression model reported a higher baseline St George's Respiratory Questionnaire (SGRQ) total score as a significant predictor of mortality (hazard ratio 1.037 [95% confidence interval 1.021-1.054]; p<0.0001). The 36-item short-form health survey (SF-36) mental and physical component scores were also predictive of an increased mortality risk (p<0.05). Age, forced expiratory volume in 1 s (FEV(1)), body mass index and smoking status were not significant predictors. Spline analysis of baseline variables revealed a linear association between SGRQ total score and mortality risk over 1 year (logarithmic scale). Other baseline variables, including FEV(1), showed different bimodal patterns in the spline analysis. There was no difference in mortality in the formoterol versus the non-formoterol treatment group while budesonide-containing treatment was associated with reduced 1-year, all-cause, in-study mortality compared with non-budesonide therapy.
  
  
  CONCLUSIONS
  Health status measured by SGRQ and SF-36 may be important for predicting COPD patients at increased mortality risk, with SGRQ total score emerging as the strongest predictor compared with other baseline covariates.
authors.affiliation: Royal Devon & Exeter Hospital, Barrack Road, Exeter, EX2 5DW, UK. d.m.g.halpin@ex.ac.uk
authors.forename: David M G
authors.initials: DM
authors.lastname: Halpin
authors.forename: Stefan
authors.initials: S
authors.lastname: Peterson
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Larsson
authors.forename: Peter M A
authors.initials: PM
authors.lastname: Calverley
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001993:Bronchodilator Agents / Q000627:therapeutic use; D019819:Budesonide / Q000627:therapeutic use; D004983:Ethanolamines / Q000627:therapeutic use; D005260:Female; D005541:Forced Expiratory Volume; D000068759:Formoterol Fumarate; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy / Q000401:mortality* / Q000503:physiopathology; D016032:Randomized Controlled Trials as Topic; D012044:Regression Analysis; D012129:Respiratory Function Tests; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D001993:Bronchodilator Agents; D004983:Ethanolamines; D019819:Budesonide; D000068759:Formoterol Fumarate