Circulating eosinophil levels and lung function decline in stable chronic obstructive pulmonary disease: a retrospective longitudinal study.

Objective: Whether blood eosinophils (bEOS) in chronic obstructive pulmonary disease (COPD) are associated with disease progression is a topic of debate. We aimed to evaluate whether the differential white blood cell (WBC) count, symptoms and treatment may predict lung function decline and exacerbations in COPD patients.

Methods: We retrospectively examined stable COPD patients with a minimum follow-up of 3 years at our outpatients' clinic.