Erdosteine, but Not N-Acetylcysteine, is Associated with Improved Homogeneity of Alveolar Ventilation in Patients with Mild-to-Moderate COPD Treated with LABA/LAMA

Purpose

Ventilation inhomogeneity and impaired alveolar ventilation (VA) are important abnormalities in chronic obstructive pulmonary disease (COPD) and may persist despite optimized bronchodilator therapy. Volumetric capnography (VCap) assesses uneven ventilation distribution in peripheral lung units. This study compared erdosteine and N-acetylcysteine (NAC), added to long-acting β2-agonist/long-acting muscarinic antagonist (LABA/LAMA) therapy, on VCap-derived indices and VA in mild-to-moderate COPD. Patients and methods: This retrospective study analyzed anonymized data from clinically stable patients receiving LABA/LAMA therapy. Patients were classified according to treatment received during the preceding four weeks: erdosteine 600 mg/day plus LABA/LAMA, NAC 600 mg/day plus LABA/LAMA, or LABA/LAMA alone. VCap indices ─ time to peak tidal expiratory flow/expiratory time ratio (TPTEF/TEX), Phase 2/Phase 3 angle (S2/S3 angle), dead-space-to-tidal-volume ratio (VD/VT) ─ and VA were assessed at baseline and after four weeks. Comparisons were performed using analysis of variance and adjusted linear mixed-effects models.