Association of inhaled corticosteroid use with first Pseudomonas aeruginosa isolation in eosinophilic bronchiectasis: a multicenter retrospective study.

BACKGROUND

The use of inhaled corticosteroids (ICS) in bronchiectasis patients with eosinophilic inflammation is controversial due to the potential risk of bronchial or pulmonary infection. This study examined the association between ICS use and first Pseudomonas aeruginosa isolation across strata of blood eosinophil count (BEC).

METHODS

A multicenter retrospective study was conducted in patients with bronchiectasis, who were classified according to baseline BEC at cohort entry: HighBEC (≥300 cells/μL), InterBEC (100-299 cells/μL), and LowBEC (<100 cells/μL). ICS use was identified from prescription records, and first P. aeruginosa isolation was defined as the first positive culture for P. aeruginosa from a lower respiratory tract sample after cohort entry. Multivariate Cox proportional hazards regression was used to quantify the risk of first P. aeruginosa isolation associated with ICS use.

RESULTS

Of 1900 bronchiectasis patients assessed, 719 were analyzed: 194 (27.0%) received ICS, 525 (73.0%) did not. During follow-up, P. aeruginosa was detected in 69 (9.6%) patients. After adjustment for potential confounders and disease severity indicators, ICS use was associated with a significantly higher risk of first P. aeruginosa isolation in patients with BEC ≥ 100 cells/μL, using no ICS as reference (HighBEC: adjusted HR 4.15, 95% CI 1.29-13.38, P = 0.0172; InterBEC: adjusted HR 3.13, 95% CI 1.56-6.27, P = 0.0013), but not in LowBEC patients (adjusted HR 0.48, 95% CI 0.08-2.79, P = 0.4160). Propensity-matched analyses supported these findings.

CONCLUSION

ICS use was associated with an increased risk of first P. aeruginosa isolation in eosinophilic bronchiectasis, suggesting caution when prescribing ICS to these patients.