Clinical Characteristics and Risk of Exacerbations Associated With Different Diagnostic Criteria of Asthma-COPD Overlap.

Introduction: There is currently no universally accepted definition of asthma-COPD overlap (ACO).

Objective: To compare the prevalence of ACO in patients with asthma or COPD, and to assess their clinical characteristics and the capacity of the different definitions to predict the risk of exacerbation.

Method: Prospective observational study with a 12-month follow-up in an asthma cohort and a COPD cohort. Four diagnostic criteria were compared: A) the Spanish 2012 consensus; B) the 2016 international consensus; C) the 2017 consensus between the Spanish COPD guidelines (GesEPOC) and GEMA asthma guidelines; and D) the single criterion of ≥300eosinophils/μL, proposed by GOLD 2019. The risk of exacerbations was evaluated in each group.

Results: A total of 345 patients were included, 233 (67.5%) with COPD and 112 (32.5%) with asthma, aged 63±14 years, 70.4% men. Fifteen (4.3%) patients met the criteria for ACO according to the criteria described under A above; 30 (8.7%) with the criteria of B; 118 (34.2%) with the criteria of C; and 97 (28.1%), with the D criterion. The ACO-COPD subtype were older, had worse lung function, and an increased risk of exacerbation compared with the ACO-asthma group. Of all the definitions evaluated, those which distinguished a higher risk of exacerbations were the GesEPOC-GEMA consensus and the GOLD proposal.

Conclusions: The prevalence of ACO varies enormously depending on the diagnostic criteria used. The ACO population is heterogeneous, and the ACO-COPD subtype is very different from the ACO-asthma subtype. The definitions that include eosinophilia identify ACO patients with a greater risk of exacerbation.