The asthma COPD overlap syndrome (ACOS)

Curr Allergy Asthma Rep. 2015 Mar;15(3):509. doi: 10.1007/s11882-014-0509-6.


Asthma and chronic obstructive pulmonary disease (COPD) have traditionally been viewed as distinct clinical entities. Recently, however, much attention has been focused on patients with overlapping features of both asthma and COPD: those with asthma COPD overlap syndrome (ACOS). Although no universal definition criteria exist, recent publications attempted to define patients with ACOS based on differences in clinical features, radiographic findings, and diagnostic tests. Patients with ACOS make up a large percentage of those with obstructive lung disease and have a higher overall health-care burden. Identifying patients with ACOS has significant therapeutic implications particularly with the need for early use of inhaled corticosteroids and the avoidance of use of long-acting bronchodilators alone in such patients. However, unlike asthma and COPD, no evidence-based guidelines for the management of ACOS currently exist. Future research is needed to improve our understanding of ACOS and to achieve the best management strategies.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adrenal Cortex Hormones / therapeutic use
  • Asthma / complications
  • Asthma / drug therapy*
  • Asthma / epidemiology
  • Bronchodilator Agents / therapeutic use
  • Clinical Trials as Topic
  • Glucocorticoids / therapeutic use
  • Humans
  • Pulmonary Disease, Chronic Obstructive / complications
  • Pulmonary Disease, Chronic Obstructive / drug therapy*
  • Pulmonary Disease, Chronic Obstructive / epidemiology
  • Pulmonary Disease, Chronic Obstructive / physiopathology


  • Adrenal Cortex Hormones
  • Bronchodilator Agents
  • Glucocorticoids