Abstract Rationale Bronchiectasis exhibits significant geographic variations globally. While European registries like EMBARC have established comprehensive databases, Latin American data remain scarce. This study characterized the Argentine Bronchiectasis Registry (ReBroAr) and compared it with EMBARC to identify unique regional patterns. Methods This multicenter, prospective observational study enrolled 1,288 adult patients with bronchiectasis. Comprehensive data included demographics, etiology, pulmonary function, microbiological cultures, severity scores, and treatment patterns. Patients underwent thorough etiological investigation including immunologic, microbiological, and genetic testing when indicated. Results Mean age was 60.7 years with marked female predominance (69% vs 34% EMBARC, p 0.001). Most patients (71.6%) were never-smokers. Microbiological analysis revealed 50.3% had no bacterial isolation. Among positive cultures, Pseudomonas aeruginosa predominated (21.7%), followed by other bacteria (12.6%), Haemophilus influenzae (11.3%), and Staphylococcus aureus (4.1%). Pseudomonas aeruginosa chronic infection affected only 16.4% of patients. Etiological distribution differed significantly from EMBARC. Post-infectious causes accounted for 28.5% (vs 21.2% EMBARC), with post-tuberculosis etiology notably elevated at 16.9% versus 4.9% (3.4-fold higher, p 0.001). Idiopathic classification was 2.5-fold lower (15.5% vs 38.1%, p 0.001). COPD-associated bronchiectasis represented 10.3% and asthma-associated 10.2%.Spirometric obstruction was present in 39.6%, intermediate between EMBARC (34%) and USA registries (51%). Disease severity revealed predominantly mild disease: FACED score showed 61.1% mild, 31.2% moderate, 7.7% severe; E-FACED demonstrated 71.8% mild, 23.7% moderate, 4.5% severe.Clinical presentation included cough (87%), sputum production (69%), and dyspnea (62%). Eosinophilia was present in 52.5%. Bronchodilator response was positive in only 17% despite high asthma association. There was a predominance of involvement of the lower lobes (51-55%).Treatment patterns revealed 67.8% used inhaled corticosteroids: 44.9% on ICS/LABA combinations, 20.4% on triple therapy, and 14.4% untreated. Conclusions ReBroAr reveals unique epidemiological patterns: female predominance, 3.4-fold higher post-tuberculous etiology versus EMBARC, and lower idiopathic classification reflecting comprehensive etiological investigation. The relatively low Pseudomonas aeruginosa chronic infection rate (16.4%) and 50.3% without bacterial isolation suggest distinct microbiological patterns. Predominantly mild-to-moderate severity despite significant symptoms and high inhaled corticosteroid use (67.8%) suggests opportunities for optimizing phenotype-specific therapy. These findings emphasize the importance of regional registries in understanding bronchiectasis heterogeneity and informing population-specific management approaches. This abstract is funded by: None
Baran et al. (Fri,) studied this question.