Asthma-chronic obstructive pulmonary disease overlap: Results from a national-multicenter study.

Introduction:Patients with asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) have a greater disease burden than those with COPD or asthma alone. In this study, it was aimed to determine the prevalence, risk factors, and clinical features of ACO because there are limited national data in Türkiye. Materials and Methods:The study was conducted in a cross-sectional design in nine tertiary-care hospitals. The patients followed with a diagnosis of asthma or COPD for at least one year were enrolled in the study. The frequency of ACO and the characteristics of the patients were evaluated in the asthma and COPD groups. Result:The study included 408 subjects (F/M= 205/203, mean age= 56.24 ± 11.85 years). The overall prevalence of ACO in both groups was 20.8% (n= 85). The frequency was higher in the COPD group than in the asthma group (n= 55; 33.3% vs. n= 22; 9.8%), respectively (p= 0.001). Patients with ACO had similarities to patients with COPD in terms of advanced age, sex, smoking, exposure to biomass during childhood, being born in rural areas, and radiologic features. Characteristics such as a history of childhood asthma and allergic rhinitis, presence of chronic sinusitis, NSAID hypersensitivity, atopy, and high eosinophil counts were similar to those of patients with asthma (p<0.001). The annual decline in FEV1 was more prominent in the ACO group (mean= -250 mL) than in the asthma (mean change= -60 mL) and COPD (mean change= -230 mL) groups (p= 0.003). Conclusions:This study showed that ACO was common among patients with asthma and COPD in tertiary care clinics in our country. ACO should be considered in patients with asthma and COPD who exhibit the abovementioned symptoms.