Pneumonia as comorbidity in chronic obstructive pulmonary disease (COPD). Differences between acute exacerbation of COPD and pneumonia in patients with COPD.

INTRODUCTION: Pneumonia is considered an independent entity in chronic obstructive pulmonary disease (COPD), to be distinguished from an infectious exacerbation of COPD. The aim of this study was to analyze the clinical characteristics and progress of the exacerbation of COPD (ECOPD) compared to pneumonia in COPD (PCOPD) patients requiring hospitalization.

PATIENTS AND METHODS: Prospective, longitudinal, observational cohort study including 124 COPD patients requiring hospital admission for lower respiratory tract infection. Patients were categorized according to presence of ECOPD (n=104) or PCOPD (n=20), depending on presence of consolidation on X-ray. Demographic, clinical, laboratory, microbiological and progress variables were collected.

RESULTS: Patients with ECOPD showed more severe respiratory disease according to the degree of obstruction (P<.01) and need for oxygen therapy (P<.05). PCOPD patients showed increased presence of fever (P<.05), lower blood pressure (P<.001), more laboratory abnormalities (P<.05; leukocytosis, elevated CRP, low serum albumin) and increased presence of crepitus (P<.01). Microbiological diagnosis was achieved in 30.8% of cases of ECOPD and 35% of PCOPD; sputum culture yielded the highest percentage of positive results, predominantly Pseudomonas aeruginosa. Regarding the progress of the episode, no differences were found in hospital stay, need for ICU or mechanical ventilation.

CONCLUSIONS: Our data confirm clinical and analytical differences between ECOPD and PCOPD in patients who require hospital admission, while there were no differences in subsequent progress.