Chronic Airway Disease, Mucus Rheology and Exacerbations

The main objective of this trial is to compare the exacerbation number over 12 months of follow-up between a group of patients with COPD treated according to standardized management (azithromycin prescribed in the event of severe sputum according to the CASA-Q score , standardized comparator arm) and a similar group in which azithromycin is prescribed based on mucus rheology (experimental arm) or CASA-Q.

Inclusion Criteria: * Subjets between 40 - 85 years (included) * Written and signed informed consent form * Subjects must be able to attend all planned visits and comply with all test procedures * Beneficiary of or affiliated with the French social security system * Man or woman with chronic obstructive pulmonary disease for at least 1 year defined according to Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria and validated by the clinical investigator * Optimal treatment according to GOLD class severity C or D recommendations * \>=3 exacerbation (regardless of severity: mild-moderate-severe) or ≥ 1 severe exacerbations (requiring hospitalization) in the past 12 months * Spontaneous or induced sputum production * Electrocardiogram: corrected distance between Q and T waves (QTC) \