Impact of Bronchiectasis Severity on Clinical Outcomes in Patients With Allergic Bronchopulmonary Aspergillosis: A Retrospective Cohort Study

Abstract

Background

The impact of bronchiectasis severity on the outcomes of patients with allergic bronchopulmonary aspergillosis (ABPA) remains uncertain.

Objective

To evaluate whether bronchiectasis severity is associated with an increased risk of ABPA exacerbations.

Methods

We retrospectively analyzed patients with ABPA between 2007 and 2019. Patients were categorized based on the segments involved by bronchiectasis as mild (1-5), moderate (6-9), and extensive (≥10). We compared lung function and immunological markers among the groups. A multivariable Poisson regression analysis, using follow-up duration as an offset variable, assessed the association between bronchiectasis severity and ABPA exacerbations, adjusting for key confounders. We report the association as an adjusted relative rate (aRR) with 95% confidence intervals (CI).

Results

We included 705 patients with ABPA (mean age, 35 years). Of these, 219 (31.1%), 226 (32.1%), and 260 (36.9%) had mild, moderate, and extensive bronchiectasis, respectively. Patients with extensive bronchiectasis had poorer lung function and elevated immunological markers (serum total IgE, Aspergillus fumigatus-IgE, and A. fumigatus-IgG) than those with mild or moderate bronchiectasis. The exacerbation frequency increased with the severity of bronchiectasis (mild: 41.5% vs moderate: 53.4% vs extensive: 57.7%, P = .005). On multivariable analysis, the risk of ABPA exacerbation increased significantly with bronchiectasis severity (aRR [95% CI]; extensive: 1.51 [1.09-2.08], moderate: 1.50 [1.09-2.08]). In addition, increasing age (aRR, 0.84 [95% CI, 0.76-0.94]) and body mass index (aRR, 0.97 [95% CI, 0.94-0.99]) were associated with lower exacerbation risk after adjusting for total IgE, lung function, and high-attenuation mucus.

Conclusion

Moderate-to-extensive bronchiectasis is associated with worse lung function, heightened immunological severity, and an increased risk of ABPA exacerbation.