Chronic obstructive pulmonary disease severity and cardiovascular outcomes

To identify predictors of chronic obstructive pulmonary disease (COPD) severity and assess the relation between COPD severity and risk of cardiovascular outcomes.

A cohort of patients with diagnosed and treated COPD was compiled from the Saskatchewan Health longitudinal databases. We used multivariate modeling to identify predictors of hospitalization for COPD as an indicator of COPD severity, and we used the model to characterize patients according to quintiles of COPD severity. These severity levels were used as independent variables in multivariate models of cardiovascular outcomes.

Determinants of COPD severity included emphysema, recent nebulizer use, home oxygen services, corticosteroid use, frequent bronchodilator use, pneumonia and prior COPD exacerbation. The 20% of patients with the highest COPD severity were 1.27 (CI: 1.07-1.50) times more likely to have arrhythmia, 1.25 (CI: 1.07-1.46) times more likely to have ischemic heart disease, 1.38 (CI: 1.11-1.71) times more likely to have angina, 2.28 (CI: 1.95-2.66) times more likely to have congestive heart failure, and 1.63 (CI: 1.22-2.16) times more likely to die of cardiovascular causes than the least severe 20% of patients.

Patients with more severe COPD, as defined by our model, had higher cardiovascular morbidity and mortality than patients with less severe COPD.