Pulmonary Rehabilitation with Airway Clearance Techniques Improves Mucus Hypersecretion and Clinical Outcomes in COPD: A Retrospective Study.

Abstract

Objective: To evaluate the effects of a pulmonary rehabilitation (PR) program incorporating airway clearance techniques Active Cycle of Breathing Technique (ACBT) and Oscillatory Positive Expiratory Pressure (OPEP) on mucus hypersecretion, pulmonary function, and quality of life in patients with chronic obstructive pulmonary disease (COPD).

Methods: This single-center, retrospective observational study included 118 hospitalized patients with stable moderate COPD and sputum hypersecretion between April 2024 and July 2025. Patients received either PR combined with ACBT and OPEP (PR+ACBT/OPEP, n = 56) or conventional PR with basic breathing training (n = 62). Primary outcomes were sputum volume, sputum viscosity, and responder rate (≥20% viscosity reduction). Secondary outcomes included pulmonary function parameters, symptom burden assessed by the COPD Assessment Test (CAT) and modified Medical Research Council (mMRC) scale, and treatment adherence.

Results: Baseline characteristics were comparable between groups. Adherence was high in both groups, and no serious adverse events were observed. At discharge, the PR+ACBT/OPEP group demonstrated significantly greater reductions in sputum volume (-6.8 mL; P < 0.001) and viscosity (-46 mPa·s; P < 0.001) than controls, with a higher responder rate (69.6% vs. 29.0%). Improvements in pulmonary function were more pronounced in the PR+ACBT/OPEP group, including FEV₁, FEV₁%pred, and small-airway indices. Symptom burden was also reduced, with greater declines in CAT scores and a higher proportion of patients achieving the minimal clinically important difference. The mMRC grade improved in the PR+ACBT/OPEP group but remained unchanged in controls.

Conclusion: In this retrospective, single-center study, the integration of ACBT and OPEP into pulmonary rehabilitation was associated with improved mucus clearance, lung function parameters, and patient-reported outcomes in COPD patients with chronic sputum hypersecretion. These findings should be interpreted as exploratory and hypothesis-generating, supporting the potential role of airway clearance techniques within pulmonary rehabilitation and warranting confirmation in prospective, multicenter studies.