Pulmonary embolism in chronic obstructive pulmonary disease: A population-based cohort study

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.