Increased risk of community-acquired pneumonia in COPD patients with comorbid cardiovascular disease

COPD patients with community-acquired pneumonia (CAP) have worse clinical outcomes, as compared to those without COPD. Cardiovascular disease (CVD) is a common comorbidity for COPD patients. Whether COPD with comorbid CVD will increase the risk of CAP is not well investigated. The incidence and factors associated with CAP in COPD patients with and without CVD were analyzed. The medical records of patients with newly diagnosed COPD between 2007 and 2010 were reviewed. The patients' characteristics, medical history of CVD, occurrence of CAP, and type of medication were recorded. Kaplan-Meier curves were used to assess the differences in cumulative incidence of CAP. Cox's proportional hazards regression model was used to determine the adjusted hazard ratios with 95% confidence intervals in relation to factors associated with CAP in COPD patients with and without CVD. Among 2,440 patients, 475 patients (19.5%) developed CAP during the follow-up period. COPD patients who developed CAP were significantly older, had lower forced expiratory volume in 1 second, frequent severe exacerbation and comorbid CVD, as well as received inhaled corticosteroid (ICS)-containing therapy than those without CAP. The cumulative incidence of CAP was higher in COPD patients with CVD compared to those without CVD. Patients who received ICS-containing therapy had significantly increased risk of developing CAP compared to those who did not. For patients with COPD, comorbid CVD is an independent risk factor for developing CAP. ICS-containing therapy may increase the risk of CAP among COPD patients.