MECHANISMS OF ALLERGY AND ADULT ASTHMA: Edited by J. Andrew Grant and Enrico HefflerAsthma/obstructive pulmonary disease overlap: update on definition, biomarkers, and therapeuticsGeneroso, August; Oppenheimer, JohnAuthor Information Allergy & Immunology Department, Rutgers New Jersey Medical School, The State University of New Jersey, Newark, New Jersey, USA Correspondence to John Oppenheimer, MD, Rutgers New Jersey Medical School, The State University of New Jersey, Mailing Address: 8 Saddle Road, Cedar Knolls, NJ 07927, USA. Tel: +1 973-972-2500; fax: +1 973-540-0472; e-mail: [email protected] Current Opinion in Allergy and Clinical Immunology: February 2020 - Volume 20 - Issue 1 - p 43-47 doi: 10.1097/ACI.0000000000000596 Buy Metrics Abstract Purpose of review Asthma/chronic obstructive pulmonary disease overlap (ACO) continues to be a poorly understood condition. This review discusses newly proposed criteria and potential biomarkers in ACO, to aid in diagnosis and research studies, and prudent therapeutic approaches. Recent findings A global expert panel proposed an operational definition consisting of major and minor criteria as a step toward defining ACO. Serum periostin and YKL-40 may serve as biomarkers for ACO. Clinically, a reasonable therapeutic approach to ACO is the early addition of a long-acting β-agonist (LABA) and/or a long-acting muscarinic antagonist (LAMA) to an inhaled corticosteroid (ICS). Summary Both the proposed criteria and the described biomarkers for ACO can help guide clinicians in identifying this condition as well as aid researchers in designing much needed future studies. In the meantime, clinicians can treat potential ACO patients using the above approach, until therapeutic studies in clearly defined ACO patients are performed. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.