Introduction: Inhaled antibiotics are recommended by ERS guidelines for the treatment of patients with bronchiectasis, but results of individual studies are inconsistent.

Methods: Systematic review and meta-analysis of randomised controlled trials of inhaled antibiotics in adult patients with bronchiectasis. Eligible studies were identified through MEDLINE, Embase and CENTRAL and included if patients were adults with stable bronchiectasis diagnosed by CT and trials had a treatment duration ? 4 weeks. Efficacy was evaluated through effects on exacerbations, bacterial load, symptoms, quality of life and FEV1. Data were pooled through random-effects meta-analysis. The study was registered on PROSPERO CRD42023384694.

Results: Twenty studies involving 3468 patients were included. Inhaled antibiotics were associated with reduced number of subjects with exacerbations (risk ratio 0.85 95%CI 0.75-0.96), reduced exacerbation frequency (rate ratio 0.78 95%CI 0.68-0.91), reduced severe exacerbations frequency (rate ratio 0.48 95%CI 0.31-0.74) and prolonged time to first exacerbation (hazard ratio 0.80 95%CI 0.68-0.94). There was a significant effect on quality of life using the SGRQ (-3.13 95%CI -5.93 to -0.32) and the QOL-B questionnaire (2.51 95%CI 0.44 to 4.31). Bacterial load was consistently reduced but FEV1 was not affected. There was no difference in adverse effects between groups (odds ratio 0.99 95%CI 0.75-1.30). Antibiotic resistant organisms were increased by treatment.

Conclusions: Inhaled antibiotics reduce exacerbations, severe exacerbations and improve symptoms and quality of life in adults with bronchiectasis.