Prognosis of COPD patients requiring frequent hospitalization: role of airway infection

Abstract

Rationale: A subgroup of patients with chronic obstructive pulmonary disease require frequent hospitalization because of exacerbations of the disease. We hypothesized that airway infection by non-usual pathogens is a major factor driving hospitalization needs in these patients.

Objectives: 1) To describe the clinical and functional characteristics of a cohort of COPD patients requiring > or =2 hospitalizations per year; 2) to determine prospectively their microbiological pattern during exacerbations; and, 3) to analyze the prognostic value of several clinical, functional and microbiological variables with respect to hospitalizations and mortality.

Methods: Open cohort study of 116 COPD patients who had been hospitalized at least twice during the last 12 months. Patients were followed for an average of 21 months.

Measurements and main results: Clinical data, forced spirometry and 6min walking distance were determined, and the BODE index was calculated, at the time of inclusion in the study. During follow-up, sputum culture was obtained during exacerbations, and hospitalization and mortality were collected every two months. Mean age was 71 yrs, and 94% of patients were male. Main findings show that: 1) not all patients had severe disease according to either the degree of airflow limitation or the BODE index; 2) non-usual pathogens, mainly Pseudomonas aeruginosa, other gram-negative non-fermentative rods and Enterobacteriaceae, were isolated among 71.1% of the sputum obtained during exacerbations; and, 3) these pathogens were associated with poor prognosis and frequent hospitalization.

Conclusions: Airway infection by non-usual pathogens appears to be a key driver of frequent hospitalizations and mortality in COPD.