title: Chronic obstructive pulmonary disease in primary care: an epidemiologic cohort study from the Canadian Primary Care Sentinel Surveillance Network.
abstract: BACKGROUND
  Chronic obstructive pulmonary disease (COPD) is mostly managed within primary care, but there is little Canadian evidence from this setting. This study was undertaken to determine the prevalence of physician-diagnosed COPD in primary care practices, and the degree of comorbidity with other chronic conditions, and to assess patterns of medication prescribing.
  
  
  METHODS
  The Canadian Primary Care Sentinel Surveillance Network is a national "network of networks" whose member practices use electronic medical records (EMRs). At the time of the study, it included data from 444 physicians from 10 networks in 8 provinces. We conducted an epidemiologic cohort study of all patients who had EMR data collected by the network at the end of 2012. Validated case-finding algorithms were used to identify cases of COPD. We used descriptive statistics and multivariate modelling analyses to calculate the prevalence of COPD, its association with key demographic factors and comorbidities, and patterns of medication prescribing.
  
  
  RESULTS
  The observed prevalence of COPD was 4.0% (10 043/250 346), which represents a population prevalence of 3.4% using age-sex standardization. Comorbidity was common, with prevalence ratios ranging from 1.1 for the presence of a single comorbid condition to 1.9 for 4 or more comorbid conditions. Anticholinergic agents (63%), short- (48%) and long-acting (38%) β-agonists and inhaled corticosteroids (41%) were the most commonly used medications.
  
  
  CONCLUSIONS
  The prevalence of physician-diagnosed COPD in Canadian primary care practices was similar to that reported in other practice-based studies at about 3%-4%. Most patients had comorbid conditions and were taking multiple medications. EMR data may be useful to assess both the epidemiology and management of COPD in primary care practices.
authors.affiliation: Centre for Studies in Primary Care, Department of Family Medicine, Queen's University, Kingston, Ont. ; Department of Public Health Sciences, Queen's University, Kingston, Ont.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Green
authors.affiliation: Department of Family Medicine, Dalhousie University, Halifax, NS.
authors.forename: Nandini
authors.initials: N
authors.lastname: Natajaran
authors.affiliation: Division of Respiratory and Critical Care Medicine, Department of Medicine, Queen's University, Kingston, Ont.
authors.forename: Denis E
authors.initials: DE
authors.lastname: O'Donnell
authors.affiliation: Centre for Studies in Primary Care, Department of Family Medicine, Queen's University, Kingston, Ont.
authors.forename: Tyler
authors.initials: T
authors.lastname: Williamson
authors.affiliation: Centre for Studies in Primary Care, Department of Family Medicine, Queen's University, Kingston, Ont.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Kotecha
authors.affiliation: Department of Family Medicine, University of Alberta, Edmonton, Alta.
authors.forename: Shahriar
authors.initials: S
authors.lastname: Khan
authors.affiliation: Department of Family Medicine, University of Alberta, Edmonton, Alta.
authors.forename: Andrew
authors.initials: A
authors.lastname: Cave
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