Community-acquired pneumonia in patients with and without chronic obstructive pulmonary disease

The purpose of this study was to analyse the possible differences, especially those regarding mortality, between patients hospitalized for community-acquired pneumonia (CAP) with and without chronic obstructive pulmonary disease (COPD), and the risk factors related to mortality in the COPD group.

710 patients with CAP were included in a prospective multicenter observational study. 244 of the patients had COPD confirmed by spirometry.

COPD was associated with mortality in patients with CAP (OR=2.62 CI: 1.08-6.39). Patients with COPD and CAP had a significantly higher 30-day mortality rate as compared to patients without COPD. Multivariate analysis showed that PaO(2)< or =60 mmHg (OR=7.95; 95% CI: 3.40-27.5), PaCO(2)> or =45 mmHg (OR=4.6; CI: 2.3-15.1); respiratory rate > or =30/min (OR=12.25; CI: 3.45-35.57), pleural effusion (OR=8.6; 95% CI: 2.01-24.7), septic shock (OR=12.6; 95% CI: 3.4-45.66) and renal failure (OR=13.4; 95% CI: 3.2-37.8) were significantly related to mortality. Purulent sputum and fever were considered as protective factors.

COPD was an independent risk factor for mortality in patients with CAP. Hypoxemia and hypercapnia are associated with mortality in patients with CAP with and without COPD. Chronic obstructive pulmonary disease and PaCO(2) value could be useful prognostic factors and should be incorporated in risk stratification in patients with CAP.