Abstract
Background The role of inhaled corticosteroid (ICS) in chronic obstructive pulmonary disease (COPD) is unclear. Hence, this study aimed to evaluate the efficacy of ICS as an add-on to long-acting muscarinic antagonist (LAMA)/long-acting beta 2 agonist (LABA), which was assessed using the impulse oscillation system (IOS), in patients with COPD. Methodology We included patients with COPD whose treatment was changed from LAMA/LABA (≥four weeks) to ICS/LAMA/LABA between April 2019 and March 2021. To gain insight into the effect and safety of ICS-containing triple therapy for COPD, pulmonary function; Short-Form 36, St. George's Respiratory Questionnaire, COPD Assessment Test, and modified Medical Research Council scores; and airway resistance assessed using the IOS from one week before LAMA/LABA was switched to ICS/LAMA/LABA therapy until more than eight but less than twelve weeks after switching were evaluated. Results In total, 46 patients with COPD (mean age: 72.28 ± 7.81 years) were included in the study. None of the pulmonary function test parameters significantly changed from baseline values (mean difference in forced expiratory volume in one second [FEV1.0]: +0.032, P = 0.12; percentage FEV1.0 [FEV1.0%]/forced vital capacity [FVC]: -0.58, P = 0.42; and FVC: +0.087, P = 0.058). Meanwhile, the IOS showed that resonant frequency (mean difference from baseline: -2.12, P < 0.0001) and bodily pain scores in the St. George's Respiratory Questionnaire (mean difference: -7.03, P = 0.031) significantly decreased. Conclusions Switching from LAMA/LABA to ICS/LAMA/LABA therapy reduces airway elasticity-to-inertial resistance ratios, which may lead to structural airway improvements in patients with COPD.