Abstract
BACKGROUND: Young adults with paediatric-onset bronchiectasis (POBE) represent a minority of bronchiectasis patients and are poorly characterised. We aimed to compare the characteristics and severity of adults with POBE to adult-onset bronchiectasis (AOBE). METHODS: Data from four EMBARC (European Multicentre Bronchiectasis Audit and Research Collaboration) centres were analysed. POBE was defined as patient-reported symptom onset before the age of 18 years, while AOBE was defined as symptom onset at or after the age of 18 years. We compared POBE to AOBE and used multivariable models to identify factors associated with disease severity, including lung function, Pseudomonas aeruginosa infection, exacerbations and hospitalisations. RESULTS: Among 1422 patients, 249 (17.5%) had POBE (mean onset age: 6.5 years) and 1173 had AOBE (mean onset age: 55.4 years). POBE patients were younger at enrolment (50.3 versus 66 years), had longer disease duration (43.3 versus 10.8 years), worse lung function (forced expiratory volume in 1 s (FEV(1)): 70.8% versus 84.2% predicted), greater radiological extent (Reiff score: 6.0 versus 4.4), higher bacterial infection rates (72.3% versus 54.6%) and more exacerbations (median: 2 versus 1 per year) compared to AOBE (p<0.001 across all comparisons). Symptom duration was independently associated with P. aeruginosa infection, hospitalisation, exacerbations and reduced FEV(1) % pred. Congenital aetiologies, such as primary ciliary dyskinesia and primary immunodeficiencies, further contributed to disease severity. CONCLUSIONS: Adults with POBE exhibit greater disease severity than those with AOBE, likely due to prolonged symptom duration and congenital aetiologies. Conventional bronchiectasis severity scores may underestimate severity in young people with POBE. Optimised care, including structured transition to adult care, may mitigate progression in POBE patients.