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.