Combination therapy of inhaled steroids and long-acting beta2-agonists in asthma–COPD overlap syndrome

Background: The efficacy of inhaled corticosteroids (ICSs)/long-acting beta2-agonist (LABA) treatment in patients with asthma–chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) compared to patients with COPD alone has rarely been examined. This study aimed to evaluate the clinical efficacy for the improvement of lung function after ICS/LABA treatment in patients with ACOS compared to COPD alone patients. Methods: Patients with stable COPD were selected from the Korean Obstructive Lung Disease (KOLD) cohort. Subjects began a 3-month ICS/LABA treatment after a washout period. ACOS was defined when the patients had 1) a personal history of asthma, irrespective of age, and wheezing in the last 12 months in a self-reported survey and 2) a positive bronchodilator response. Results: Among 152 eligible COPD patients, 45 (29.6%) fulfilled the criteria for ACOS. After a 3-month treatment with ICS/LABA, the increase in forced expiratory volume in 1 second (FEV₁) was significantly greater in ACOS patients than in those with COPD alone (240.2±33.5 vs 124.6±19.8 mL, P=0.002). This increase in FEV₁ persisted even after adjustment for confounding factors (adjusted P=0.002). According to severity of baseline FEV₁, the ACOS group showed a significantly greater increase in FEV₁ than the COPD-alone group in patients with mild-to-moderate airflow limitation (223.2±42.9 vs 84.6±25.3 mL, P=0.005), whereas there was no statistically significant difference in patients with severe to very severe airflow limitation. Conclusion: This study provides clinical evidence that ACOS patients with mild-to-moderate airflow limitation showed a greater response in lung function after 3 months of ICS/LABA combination treatment.