Asthma/Obstructive Pulmonary Disease Overlap

Update on Definition, Biomarkers, and Therapeutics

August Generoso; John Oppenheimer


Curr Opin Allergy Clin Immunol. 2020;20(1):43-47. 

In This Article

Proposed Criteria for Asthma/Chronic Obstructive Pulmonary Disease Overlap

Despite a lack of a formal definition, there is at least general agreement regarding some of the key features of ACO. Pulmonary specialty organizations from several countries, including the Czech Republic, Australia, Japan, and Spain, have published diagnostic criteria for ACO, with each varying somewhat.[4] In 2016 a global expert panel, comprised of specialists and generalists from North America, Western Europe, and Asia, agreed that to advance ACO as a unique entity, a universally accepted definition is required (even an imperfect one).[7] The panel proposed an operational definition consisting of major and minor criteria (Table 2). They defined three major criteria that must be present for the diagnosis of ACO. These included: persistent airflow limitation (post-bronchodilator FEV1/FVC < 0.70 or lower limit of normal) in patients at least 40 years old, at least 10 pack-years of tobacco smoking or equivalent indoor or outdoor air pollution exposure (e.g., biomass), documented history of asthma before the age of 40 years old or bronchodilator responsiveness in FEV1 of more than 400 ml. They also proposed three minor criteria, of which only one is necessary for diagnosis. These include: documented history of atopy or allergic rhinitis, bronchodilator response of FEV1 at least 200 ml, and 12% from baseline values on two or more visits or peripheral blood eosinophil count of at least 300 cells/ml. Although arbitrary and requiring validation, this definition may enable clinicians to better diagnose ACO and aid researchers to design studies that can further provide meaningful knowledge about ACO.