Unveiling the causes of bronchiectasis exacerbations: insights from a single-center study

Background: Bronchiectasis exacerbations are a significant contributor to morbidity and mortality. While environmental factors, such as viral infections, are well-established triggers for exacerbations, the role of intrinsic factors, particularly chronic bacterial infections, remains incompletely understood.Objectives: In this context, we sought to investigate the impact of chronic bacterial infections using the COVID-19 pandemic as a natural experiment, providing a unique opportunity to assess the effects of reduced external infections.Design: A retrospective observational cohort study was conducted involving patients with non-cystic fibrosis bronchiectasis.Methods: Data were collected via telephone interviews and medical record reviews, comparing exacerbation rates before (2019) and during (2020) the pandemic. The difference in exacerbation rates between 2020 and 2019 (delta exacerbations) served as the dependent variable in a multiple regression model.Results: Sixty-three patients were included in the analysis. Those without chronic bacterial infections showed a significant reduction in exacerbations during the pandemic: mean (SD) was 1.06 (1.3) versus 1.61 (1.3), respectively (p-value = 0.006). In contrast, no such reduction was observed in patients with chronic bacterial infections. Notably, chronic infection with Pseudomonas aeruginosa emerged as an independent predictor of sustained or increased exacerbations in 2020 (positive delta exacerbations), despite the implementation of social distancing measures.Conclusion: While social distancing effectively reduced bronchiectasis exacerbations in patients without chronic bacterial infections, those with Pseudomonas aeruginosa infections remained vulnerable to exacerbations, underscoring the importance of intrinsic disease/host factors. These findings highlight the need for targeted management strategies addressing chronic infections in patients with bronchiectasis.