Association of plasma fibrinogen concentrations and blood eosinophil counts with clinical phenotypes of COPD

Abstract

BACKGROUND: In patients with chronic obstructive pulmonary disease (COPD), the plasma fibrinogen level is associated with a decline in lung function and exacerbation of COPD. High blood eosinophil count is also associated with exacerbation of COPD in some studies but not others.OBJECTIVE: To investigate the associations between clinical phenotypes and plasma fibrinogen levels and blood eosinophil counts in patients with COPD.METHODS: Outpatients with COPD, in whom plasma fibrinogen level and blood eosinophil count were measured at least once simultaneously, were analysed retrospectively. Patients were classified into four groups, based on plasma fibrinogen level (threshold, 350 mg/dl) and blood eosinophil percentage (threshold, 2%). Clinical characteristics, comorbidities, laboratory data, COPD severity and exacerbations were compared in the four groups.RESULTS: Of 370 patients with COPD, the group with both high fibrinogen levels and eosinophil counts had more severe airflow limitation, more comorbidities and higher COPD severity indexes than the groups with low plasma fibrinogen. The annual rates of severe (0.29/year) and total (0.42/year) exacerbations were significantly higher in patients with both high fibrinogen and eosinophils than in the other three groups.CONCLUSION: Plasma fibrinogen levels and blood eosinophil counts may predict the clinical phenotype and frequency of exacerbations of COPD.