Acute exacerbations of chronic obstructive pulmonary disease: identification of biologic clusters and their biomarkers.

Rationale: Exacerbations of chronic obstructive pulmonary disease (COPD) are heterogeneous with respect to inflammation and etiology.

Objectives: Investigate biomarker expression in COPD exacerbations to identify biologic clusters and determine biomarkers that recognize clinical COPD exacerbation phenotypes, namely those associated with bacteria, viruses, or eosinophilic airway inflammation.

Methods: Patients with COPD were observed for 1 year at stable and exacerbation visits.

Procalcitonin and C-reactive protein in hospitalized adult patients with community-acquired pneumonia or exacerbation of asthma or COPD.

Background: Antibiotic overuse in respiratory illness is common and is associated with drug resistance and hospital-acquired infection. Biomarkers that can identify bacterial infections may reduce antibiotic prescription. We aimed to compare the usefulness of the biomarkers procalcitonin and C-reactive protein (CRP) in patients with pneumonia or exacerbations of asthma or COPD.