Abstract
INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is characterized by irreversible airflow limitation. While single-inhaler long-acting dual bronchodilators (LADBs) effectively relieve symptoms and improve lung function, their long-term impact on spirometry outcomes and the potential for meaningful changes in key diagnostic indices in a real-world setting remain underexplored. METHODS: This was a single-country (China), single-center, retrospective, noninterventional, real-world study that included 182 patients treated with LADBs (indacaterol/glycopyrronium [IND/GLY] or umeclidinium/vilanterol [UMEC/VI]). The primary outcomes were changes in trough FEV1 and FEV1/FVC from baseline. Secondary outcomes were changes in other spirometry parameters. An exploratory post hoc analysis explored the reversal of FEV1/FVC, defined as a posttreatment trough FEV1/FVC ratio that exceeded 70%. RESULTS: Single-inhaler LADB therapy significantly improved lung function, including FEV1, FVC, FEV1/FVC, RV, and parameters of small airway function. The least-square mean change in trough FEV1 and FEV1/FVC post-treatment was 0.154 L [95% CI: 0.09, 0.218] and 1.929% [95% CI: 0.694, 3.164], respectively, at 24 weeks. Posttreatment FEV1 exhibited a characteristic pattern: an initial increase, followed by a peak, a subsequent slight decline, and eventual stabilization. Patients with lower GOLD grades experienced greater improvement in key spirometry parameters. Notably, 21 patients (11.5%) achieved a reversal of the FEV1/FVC ratio to over 70%. Exploratory logistic regression showed that a better baseline lung function, especially FEV1/FVC ratio, was associated with an increased likelihood of achieving this threshold (OR = 1.52 [95% CI: 1.29, 1.89]). CONCLUSION: This study demonstrated significant and sustained improvements in lung function in this real-world cohort of COPD patients managed with LABA/LAMA monotherapy. A subset of patients achieved a posttreatment FEV1/FVC ratio above 70%, indicating a potentially meaningful change in airflow limitation after LADB therapy.