Multimorbidity in patients with bronchiectasis: results from the US Bronchiectasis and NTM Research Registry (US BRR)

<bold>Background:</bold> Multimorbidity, the coexistence of 2 or more chronic conditions, is insufficiently understood in patients with bronchiectasis (BE). Complex disease combinations frequently result in adverse health outcomes and substantial disease burden and require tailored treatment plans. <bold>Methods:</bold> Cross-sectional data spanning 2008-2023 from the US BRR-enrolled patients with radiologically or clinically confirmed BE were analyzed. Data on 14 conditions (BE, asthma, COPD, Alpha1, primary immunodeficiency, PCD, rheumatologic disease, IBD, ABPA, GERD, otitis/rhinosinusitis, congenital heart disease, hematologic malignancy) were evaluated. Multimorbidity was defined as having ≥2 conditions, one being BE. Demographic and clinical characteristics were compared between patients with and without multimorbidity. <bold>Results:</bold> In our study of 5,287 patients with BE (mean age 66±13 yrs, 79% female, 88% white), GERD (42%), asthma (26%), and COPD (16%) were the most prevalent comorbidities. 70% had multimorbidity, with 34% having ≥3 conditions, averaging 2.2±1.1 conditions per patient. Males had higher odds of multimorbidity than females (OR=1.4, 95%CI:1.2-1.7). A greater proportion of patients with multimorbidity had exacerbations (59% vs. 48%, p<.0001) and hospitalizations (22% vs.15%, p<.0001) in 2 years prior to enrollment, lower FEV1%pred (73% vs. 79%, p<.0001) compared to those with BE alone. <bold>Conclusion:</bold> Multimorbidity is prevalent in this cohort of patients with BE and is associated with increased exacerbations, hospitalizations, and worse lung function. Longitudinal studies are imperative in evaluating comorbidity clusters and disease trajectory in this population over time.