Initiation of inhaled antibiotic therapy in chronic airway diseases: the REPAIR registry

Background Inhaled antibiotic therapy (IAT) is increasingly used in chronic airway diseases beyond cystic fibrosis. However, the clinical context and determinants driving IAT initiation in routine practice remain insufficiently characterised. Methods REPAIR is a prospective, multicentre national registry including adult patients with chronic airway diseases at the moment of IAT initiation. This cross-sectional baseline analysis describes clinical, microbiological and phenotypic characteristics, as well as prescribing patterns. Chronic bronchial infection (CBI) was defined as ≥3 isolations of the same potentially pathogenic microorganism within 12 months. Results A total of 411 patients were included (mean age 67.9±13.8 years; 57.2% women). Patients experienced 2.6±2.2 exacerbations in the previous year and 40.4% required hospitalisation. Pseudomonas aeruginosa was isolated in 79.8% of patients and 50.6% fulfilled criteria for CBI. Colistimethate was the most frequently prescribed antibiotic (78.6%) and was strongly associated with P. aeruginosa isolation, whereas lung function, exacerbation burden and CBI status did not significantly influence antibiotic class selection. IAT was initiated during exacerbation or early convalescence in 44.3% of cases. Nebulised therapy predominated (73%), while dry powder inhaler use was associated with younger age and better lung function rather than microbiological burden. Antibiotic selection patterns were broadly similar across underlying airway disease phenotypes. Conclusions In routine clinical practice, initiation of IAT in chronic airway diseases appears predominantly microbiology-driven. Although most patients start treatment under stable conditions, a substantial proportion initiate IAT during exacerbation or early convalescence, indicating that clinical instability remains an important trigger for treatment initiation in real-world practice.