Background: Several clinical studies have evaluated the role of COPD in patients with community acquired pneumonia (CAP). We investigated the systemic inflammatory response of patients with CAP (CAP 1 COPD) and patients without associated COPD (CAP only).
Methods: Clinical, microbiologic, and immunologic data were collected from 367 prospective patients on admission to hospital during a 3-year period. Comparative analyses were performed between patients with CAP 1 COPD (n 5 117) and those with CAP only (n 5 250) and between patients with and without domiciliary use of inhaled corticosteroids (ICSs) and oral corticosteroids.
Results: Detailed characteristics of clinical severity and prognosis (mortality on hospitalization and at 30 and 90 days) were similar between the CAP 1 COPD and CAP-only groups. The readmission rate and the frequency of previous pneumonia were higher in the group of patients with CAP 1 COPD. On day 1 (admission to hospital), patients with CAP 1 COPD had significantly lower serum levels of tumor necrosis factor- a , IL-1, and IL-6 compared with the CAP-only group; levels of the remaining inflammatory biomarkers (C-reactive protein, procalcitonin, IL-8, and IL-10) were similar at days 1 and 3. The exclusion of patients with domiciliary use of ICS and oral corticosteroids confirmed lower levels of TNF- a on day 1 in patients with CAP 1 COPD. Finally, lower levels of IL-6 were found only among those patients with COPD who were currently using ICS.
Conclusions: Our prospective study demonstrates a different, disease-specific, early inflammatory pattern between patients with CAP with and without associated COPD. These findings are not completely corticosteroid mediated.