Ashtma-Chronic obstructive pulmonary disease overlap syndrome (ACOS): current evidence and future research directions

Abstract

Chronic obstructive pulmonary disease and asthma are the most frequent chronic respiratory diseases that affect the general population. For a long period of time these two conditions were considered to be separate diseases. However, it became evident that some patients share symptoms and clinical findings from both diseases. These patients are considered to represent a distinct phenotype, called asthma-COPD overlap syndrome (ACOS). However, since approximately the one third of the asthmatics smoke the ACOS may primarily define those patients. This is a relatively newly defined clinical syndrome whose underlying mechanisms and most appropriate management remain to be confirmed. In this review, we summarize current knowledge on this syndrome, aiming to update clinicians and help their daily practice.