title: Geographic variation in chronic obstructive pulmonary disease exacerbation rates.
abstract: BACKGROUND
  Exacerbations are important disease events for patients with chronic obstructive pulmonary disease (COPD) as they are relatively frequent, result in significant resource use and can indicate worsening disease. Little is known about variation in COPD exacerbation rates across a health system in various geographic regions.
  
  
  OBJECTIVE
  To compare COPD exacerbation rates by regional service networks called Veterans Integrated Service Network (VISN) in the Veterans Health Administration (VA) system.
  
  
  METHODS
  Retrospective, observational study.
  
  
  METHODS
  Patients with a COPD diagnosis from October 1999 to September 2000 with follow-up to September 2002.
  
  
  METHODS
  Acute exacerbations of COPD during the baseline and follow-up periods.
  
  
  RESULTS
  A total of 198,981 patients were identified. Average exacerbation rate at baseline was 0.503 events per person per year. In the follow-up period, there were 187,686 exacerbations experienced by 87,494 persons (44.0% of cohort). During follow-up, the average adjusted exacerbation rate was 0.589 per person per year and varied from 0.335 (95% CI, 0.328-0.342) in VISN 1 to 0.749 (95% CI, 0.735-0.0.763) in VISN 9. Using the median rate of exacerbation during the baseline period as the referent, 9 VISNs had lower adjusted rate ratios and 12 VISNs had higher adjusted rate ratios in the follow-up period.
  
  
  CONCLUSIONS
  Geographic variation in the VA VISN system supports evidence that the medical care system including provider factors, and less so patient factors, affect COPD exacerbations. Understanding the reasons underlying this variation in COPD exacerbation rates may lead to improvements in future care and outcomes.
authors.affiliation: Center for Management of Complex Chronic Care, Hines VA Hospital, Hines, IL, USA. joo@uic.edu
authors.forename: Min J
authors.initials: MJ
authors.lastname: Joo
authors.forename: Todd A
authors.initials: TA
authors.lastname: Lee
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Weiss
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology; D014728:Veterans / Q000706:statistics & numerical data*