Clinical features of bronchiectasis according to age in the US Bronchiectasis Research Registry

<bold>Background:</bold> Advanced age contributes to higher bronchiectasis severity index (BSI) scores thus higher mortality and future exacerbation rates. It is not clear if bronchiectasis worsens with age or if severity of certain features of bronchiectasis are independent of age. <bold>Objective:</bold> To compare clinical features (BSI, lung function, exacerbations) of bronchiectasis according to age in the US Bronchiectasis Research Registry (BRR). <bold>Methods:</bold> Clinical features of bronchiectasis were compared according to BSI age cut-points at enrollment: 30-49, 50-69, 70-79, and 80-89 years using chi-square (categorical variables) and F-tests (continuous). <bold>Results:</bold> 3,379 subjects in the BRR were analyzed. BSI was significantly higher with increased age (mean (SD) = 3.7(3.58), 5.1(2.93), 7.2(3.05), 9.3(2.88), in ascending age groups, p<0.001). Excluding age as a risk factor, BSI scores were highest in younger patients (3.7(3.58), 3.1(2.93), 3.2(3.05), 3.3(2.88), respectively, p=0.02). Older groups trended toward a higher prevalence of ≥3 affected lobes compared to younger cohorts (59%, 63%, 67%, 68%, respectively, p=0.02) and higher prevalence of low body mass index (9%, 12%, 14%, 17%, respectively, p=0.02). The youngest group exhibited a decreasing trend in FEV1 %predicted compared to older counterparts (72, 75, 74, and 75, respectively, p=0.08) and had a higher prevalence of ≥3 exacerbations in the prior 2 years (11%, 4%, 4%, and 3%, respectively, p<0.001). <bold>Conclusion:</bold> In the US bronchiectasis registry, the youngest patients exhibit a higher frequency of exacerbations and lower lung function compared to older groups. These findings suggest that bronchiectasis progression may be independent of age.