Comparing frequencies of asthma-chronic obstructive pulmonary disease overlap in patients with stable chronic obstructive pulmonary disease

Context Asthma and chronic obstructive pulmonary disease (COPD) may share some physiological features and coexist as asthma-chronic obstructive pulmonary disease overlap (ACO). The prevalence of ACO differs according to the diagnostic criteria and study design. In patients with COPD, the prevalence of ACO varies from 5 to 55%. This study aims to examine the effect of using different diagnostic criteria on the resulting frequency of ACO in patients with COPD. Settings and design This cross-sectional observational study enrolled 60 patients with COPD randomly selected from outpatient clinics of Chest Department of Minia Cardio-Thoracic University Hospital during the period from September 2015 to September 2016. Patients and methods History, clinical examination, spirometry, and sputum cytology were done. The frequency of ACO among the 60 patients with stable COPD was separately studied based on five different diagnostic criteria (Hardin’s, Menezes, combined Hardin and Menezes, Spanish consensus, and Global Initiative for Asthma-Global Initiative for Chronic Obstructive Lung Disease criteria). Statistical analysis Statistical analysis was performed using statistical package for social science software (χ2 test and independent sample t test). Results The frequency of ACO in COPD was 40, 23.3, 16.7, 13.3, and 10% on applying combined Hardin and Menezes, Hardin’s alone, Menezes alone, the Spanish consensus, and Global Initiative for Asthma-Global Initiative for Chronic Obstructive Lung Disease criteria, respectively. Conclusion The frequency of ACO in patients with COPD decreases when using more restrictive diagnostic criteria.