How can Patients With Asthma-COPD Overlap Syndrome in Clinical Practice be Identified?

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In a recent consensus meeting of 26 Spanish specialists, 85% of the participants were in agreement about the existence of a mixed COPD-asthma phenotype, known as asthma-COPD overlap syndrome (ACOS). However, there was less agreement on the characteristics that defined this phenotype and how it can be identified in routine clinical practice.1 The need for an agreement on the significance of ACOS led to the first consensus meeting aimed at defining ACOS as a COPD phenotype. This was necessary in view of the emerging body of evidence on COPD patients with asthmatic characteristics who respond better to treatment with inhaled corticosteroids (ICS). In this meeting, major and minor criteria for the diagnosis of ACOS were defined2; however, subsequent studies have shown that these criteria were excessively restrictive, and that they applied to only a small proportion of patients who may have ACOS.3 Compared to the excessively restrictive criteria of the Spanish consensus, the recent criteria from the Global Initiative for Asthma (GINA) and the Global Initiative for Obstructive Lung Disease (GOLD) appear imprecise and ambiguous. These organizations provide a list of characteristics associated with asthma and another list of characteristics associated with COPD. Doctors are expected to tick the characteristics which apply to the patient, and if the number of ticks in each list is similar, the patient probably has ACOS.4 There is no indication of how many ticks are required, and all ticks have the same weight, even though not all characteristics have the same value when identifying asthma or COPD. Returning to the opinion of the Spanish experts, we find that the most relevant ACOS diagnostic criteria were: prior diagnosis of asthma in a COPD patient (according to 88% of experts); significant tobacco consumption (73%); and post-bronchodilator FEV1/FVC < 0.7 (69%).1