Asthma–COPD overlap: review of diagnosis and management

Abstract

Purpose of review Asthma and chronic obstructive pulmonary disease are both commonly encountered respiratory conditions. The term asthma--COPD overlap (ACO) has been used to identify patients presenting with features of both conditions. Controversy exists regarding its definition, approach to diagnosis and management. In this publication, recent evidence has been reviewed that provides insight into diagnosis and management of this condition. Recent findings Previously, multiple criteria were used to define Asthma--COPD overlap. In this publication, the most recent guidelines to identify this condition have been reviewed. This publication provides a summary of the recent evidence with regard to the role of various diagnostic modalities including the use of biomarkers, such as exhaled nitric oxide, serum IgE and provides updated evidence on available treatment choices for this condition. Summary ACO is a commonly encountered clinical condition with patients experiencing frequent exacerbations and resulting in increased healthcare resource utilization. Recent interest in ACO has led to development of a framework towards diagnosis and management of this condition. Therapeutic choices for ACO range from bronchodilator therapy to immunomodulatory therapy, highlighting the heterogeneity of this condition. Additional research is required to improve understanding of pathogenesis and improve outcomes in ACO.

Asthma-COPD overlap

“…5,10 Studies regarding FeNO for diagnosing ACO are incongruent, and more research is needed. 12 Blood eosinophils along with immunoglobulin E (IgE) are elements of the T helper 2-mediated response. 12 Elevated blood eosinophil levels are indicative of eosinophilic airway infl ammation; levels of 300 cells/mcL or greater combined with elevated serum interleukin (IL)-4 are associated with ACO.…”

“…12 Blood eosinophils along with immunoglobulin E (IgE) are elements of the T helper 2-mediated response. 12 Elevated blood eosinophil levels are indicative of eosinophilic airway infl ammation; levels of 300 cells/mcL or greater combined with elevated serum interleukin (IL)-4 are associated with ACO. Like other biomarkers, there are no clearly defi ned levels in patients with ACO.…”

“…5 Elevated IgE levels play an important role in guiding treatment with IgEspecifi c therapy in certain patients with ACO. 12 In a large multicenter observational study, evidence of sputum eosinophilia was reported to be more accurate than blood eosinophil concentration in identifying patients with more severe disease and more frequent exacerbations. 13 Sputum eosinophilia may prove to be a reliable test for diagnosing different phenotypes of chronic airway diseases; however, there is a lack of available testing, and specialized training is required for dependable testing.…”

“…13 Sputum eosinophilia may prove to be a reliable test for diagnosing different phenotypes of chronic airway diseases; however, there is a lack of available testing, and specialized training is required for dependable testing. 12,13 A 2019 study reported elevated periostin levels in both asthma and ACO but not in COPD. Serum chitinase-3-like protein 1 (YKL-40) was shown to be elevated in both COPD and ACO but not asthma.…”

“…Urinary L-histidine is promising as a biomarker for ACO. 12,15 Vascular endothelial growth factor (VEGF) is a glycosylated peptide component found in tissues with increased blood supply including lung tissue. VEGF is involved in airway remodeling.…”