Patterns of Comorbidity in Asthma-COPD Overlap Cohort According to Various ACO Definitions

Background: The asthma-COPD overlap is widely recognized, but its characteristics are not fully understood. This is largely true for the clinical presentation characterized by various ACO definitions. The purpose of this study was to investigate the pattern of comorbidities among patients with ACO, defined by various criteria. Methods: The data came from the multicenter cross-sectional study conducted in a mixed population of patients with asthma and COPD. Patients were classified into five groups according to five different definitions of ACO (GINA/GOLD/30%, Spanish criteria, COPD + asthma < 40, Gibson's criteria, clinician's diagnosis), reference ACO groups, and a group of patients with obstructive pulmonary diseases who were not diagnosed with ACO. To demonstrate the differences between groups, we compared the prevalence of comorbidities between all ACO and non-ACO groups. Data on age, severity of airflow obstruction, and smoking history were recorded for all patients. Results: For the final analysis, 1609 patients were included. Patients belonging to the ACO groups had a higher burden of comorbidities, poorer lung function, and a higher number of pack-years of smoking history compared to patients without an ACO diagnosis. Comorbidities were significantly more prevalent in ACO groups. Compared to the non-ACO group, nine diseases were more common in the GINA/GOLD/30% group, seven in both the COPD + asthma < 40 group and the clinician's diagnosis group, five in the Gibson's criteria group, and two in the Spanish criteria group. The most common comorbidities in the ACO groups were hypertension, coronary artery disease, GERD, musculoskeletal disorders, diabetes, and chronic sinusitis. Chronic sinusitis was more frequent in ACO groups defined by more precise asthma criteria. Conclusions: The definitions of ACO used in clinical practice vary widely and describe different populations. ACO populations vary in terms of comorbidities, lung function, smoking history, and age. Chronic sinusitis is a comorbidity that occurs more frequently in ACO groups defined by more precise asthma criteria. Patients with ACO differ in their clinical outcomes from those with other obstructive airway diseases.