title: Pulmonary embolism in chronic obstructive pulmonary disease: a population-based cohort study.
abstract: BACKGROUND
  To evaluate the incidence of pulmonary embolism (PE) in patients with chronic obstructive pulmonary disease (COPD) in Taiwan.
  
  
  METHODS
  This was a retrospective population-based cohort study using data retrieved from Taiwan's National Health Insurance Research Database (2000 to 2008), which contains 99% of Taiwanese healthcare data. The evaluations included 355,878 COPD patients and 355,878 non-COPD patients for comparison.
  
  
  RESULTS
  The incidence of PE in the COPD cohort was 12.31 per 10,000 person-years (1.37/10,000 persons/y), which was approximately 4-times higher than in the comparison cohort (0.35/10,000 persons/y). In the COPD cohort, risk of PE was higher in the young age group (20-59 y, HR 4.64, 95% CI 3.06-7.03) than in other age groups. Risk of PE was higher in patients with COPD combined with hypertension, coronary artery disease, and cancer, or those with previous operation (HR 4.16, 4.75, 4.56, and 4.50 respectively) than in those with COPD and no comorbidity.
  
  
  CONCLUSIONS
  The overall incidence of PE is lower in Taiwan than in western countries. However, the prevalence of PE in COPD patients is higher than in non-COPD patients and increases with age. It is crucial to incorporate PE into the differential diagnosis of COPD exacerbation for clinical physicians.
authors.affiliation: 1From the Chest Division, Department of Internal Medicine, Mackay Memorial Hospital , Taipei , Taiwan.
authors.forename: Wei-Ji
authors.initials: WJ
authors.lastname: Chen
authors.forename: Che-Chen
authors.initials: CC
authors.lastname: Lin
authors.forename: Chang-Yi
authors.initials: CY
authors.lastname: Lin
authors.forename: Yen-Jung
authors.initials: YJ
authors.lastname: Chang
authors.forename: Fung-Chang
authors.initials: FC
authors.lastname: Sung
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Kao
authors.forename: Jun-Jun
authors.initials: JJ
authors.lastname: Yeh
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D003324:Coronary Artery Disease / Q000453:epidemiology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*; D011655:Pulmonary Embolism / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D013514:Surgical Procedures, Operative / Q000706:statistics & numerical data; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult
keywords: chronic obstructive pulmonary disease; cohort study; pulmonary embolism