Copd followed in our chest diseases polyclinicfrequency of asthma-COPD overlap in diagnosed patients anddiagnostic value of prostoglandin D2

Introduction: Asthma-COPD overlap (ACO) is a disease similar to Chronic Obstructive Pulmonary Disease (COPD) with some features of asthma. Asthma-COPD is defined in the Global Initiative for Asthma (GINA) and Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines as "asthma and COPD features are accompanied at similar rates in cases with persistent airflow limitation (postbronchodilator FEV1/FVC<70%)" and criteria for diagnosis were specified. Various biomarkers have been asserted for the diagnosis of ACO in studies, but a common consensus has not been established. The number of literature evaluating Prostaglandin D2 (PGD2) in ACO is extremely restricted. Depending upon this, we aimed to assess the frequency of ACC and the value of PGD2 in diagnosis in COPD patients. Materials and Methods: Patients with COPD who applied to Erzincan Binali Yıldırım University Mengücek Gazi Training and Research Hospital Chest Diseases Outpatient Clinic were admitted consequtively between the dates 1st June 2020 and 1st June 2021 in our prospective study. Patients with COPD were evaluated using the stepwise approach related to ACO in the GINA and GOLD guidelines. When the patients were questioned in terms of COPD and asthma characteristics; presence of three or more features of both diseases was determined high risk for ACO. Among the high-risk patients, those who comply with the diagnostic criteria in the guidelines were accepted as ACO. Patients divided into two groups as COPD and AKO were compared in terms of clinical, laboratory, pulmonary function tests (PFT) and hospital admissions. The PGD2 levels of patients with ACO and COPD were measured to see if the difference was significant in the differentiation of the two groups. Findings: 84 patients with COPD were included in the study. Seventy of the patients were male and 14 of them were female, and the avarege age of the patients was 61,48 (40-84). Sixteen (19%) of the patients included in the study were diagnosed with ACO. ACO patients were younger than COPD patients, and women had a higher rate of ACO. Atopy history was higher in ACO patients than in COPD patients (p=0.001). FVC, one of the PFT parameters of the patients in the ACO group, was lower than the FEV1/FVC parameter in the COPD group (p=0.008, p=0.040), respectively. On average, the number of emergency admissions, polyclinic, and annual hospitalizations were higher in patients with ACO than in patients with COPD. Total IgE level of the ACO group was higher than that of the COPD group (p=0.035). PGD2 level was found to be significantly higher in ACO patients than in COPD patients (p<0.001). Conclusion: The frequency of patients with ACO is substantial in obstructive pulmonary diseases. We can state that these patients are more symptomatic, have more comorbidities, and have a higher frequency of hospital emergency department admissions and hospitalizations compared to asthma and COPD patients. Therefore, it is essential to distinguish these patients from asthma and COPD patients. In our study, it was concluded that PGD2 may be a significant biomarker in differentiating ACO patients from COPD patients. Keywords: COPD, Asthma-COPD overlap, Prostaglandin D2