title: Mortality among subjects with chronic obstructive pulmonary disease or asthma at two respiratory disease clinics in Ontario.
abstract: BACKGROUND
  Chronic obstructive pulmonary disease (COPD) and asthma are common; however, mortality rates among individuals with these diseases are not well studied in North America.
  
  
  OBJECTIVE
  To investigate mortality rates and risk factors for premature death among subjects with COPD.
  
  
  METHODS
  Subjects were identified from the lung function testing databases of two academic respiratory disease clinics in Hamilton and Toronto, Ontario. Mortality was ascertained by linkage to the Ontario mortality registry between 1992 and 2002, inclusive. Standardized mortality ratios were computed. Poisson regression of standardized mortality ratios and proportional hazards regression were performed to examine the multivariate effect of risk factors on the standardized mortality ratios and mortality hazards.
  
  
  RESULTS
  Compared with the Ontario population, all-cause mortality was approximately doubled among subjects with COPD, but was lower than expected among subjects with asthma. The risk of mortality in patients with COPD was related to cigarette smoking, to the presence of comorbid conditons of ischemic heart disease and diabetes, and to Global initiative for chronic Obstructive Lung Disease severity scores. Individuals living closer to traffic sources showed an elevated risk of death compared with those who lived further away from traffic sources.
  
  
  CONCLUSIONS
  Mortality rates among subjects diagnosed with COPD were substantially elevated. There were several deaths attributed to asthma among subjects in the present study; however, overall, patients with asthma demonstrated lower mortality rates than the general population. Subjects with COPD need to be managed with attention devoted to both their respiratory disorders and related comorbidities.
authors.affiliation: Granovsky-Gluskin Family Medicine Centre, Mount Sinai Hospital, Toronto, Ontario, Canada. murray.finkelstein@utoronto.ca
authors.forename: Murray M
authors.initials: MM
authors.lastname: Finkelstein
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Chapman
authors.forename: R Andrew
authors.initials: RA
authors.lastname: McIvor
authors.forename: Malcolm R
authors.initials: MR
authors.lastname: Sears
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000401:mortality*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061213:Mortality, Premature; D009864:Ontario / Q000453:epidemiology; D016012:Poisson Distribution; D016016:Proportional Hazards Models; D029424:Pulmonary Disease, Chronic Obstructive / Q000401:mortality*; D012307:Risk Factors