Asthma and chronic obstructive pulmonary disease overlap syndrome (ACOS): structured literature review and physician insights

Objectives: To understand the key characteristics of Asthma and Chronic Obstructive Pulmonary Disease Overlap Syndrome (ACOS) and to identify evidence gaps relating to the identification, treatment and management of ACOS patients. Methods: A structured literature review and 1-hour telephone interviews with specialist respiratory physicians were conducted (n=10; China, France, Germany, Japan and the USA). Results: All 10 physicians used the term ACOS in clinical practice. ACOS was not clearly defined in the literature. Prevalence of ACOS among adult patients with COPD or asthma ranged from 12–55%. ACOS patients had severe disease, with increased exacerbations and hospitalisations compared to some asthma and COPD patients. ACOS represented a clinical challenge due to a lack of evidence-based guidelines distinguishing between asthma, COPD and ACOS. Published data quantifying ACOS costs were limited. Conclusions: There is a need for consensus evidence-based guidance to facilitate earlier diagnosis and to optimise the management of ACOS patients.