The contribution of Pseudomonas aeruginosa infection to clinical outcomes in bronchiectasis: a prospective cohort study

Abstract

Objectives: The impact of Pseudomonas aeruginosa on the prognosis of bronchiectasis remains controversial. This study aimed to explore the prognostic value of P. aeruginosa in adult patients with bronchiectasis in central-southern China.

Patients and methods: This prospective cohort study enrolled 1,234 patients with bronchiectasis between 2013 and 2019. The independent impact of P. aeruginosa on all-cause mortality, annual exacerbations, and hospitalizations was assessed.

Results: P. aeruginosa was isolated from 244 patients (19.8%). A total of 188 patients died over a follow-up period of 16 (1-36) months. Patients with P. aeruginosa had a longer disease course, poorer lung function, more lung lobe involvement, and more severe Bronchiectasis Severity Index (BSI) stage than those without P. aeruginosa. The independent impact of P. aeruginosa was observed on frequent hospitalizations but not on mortality and frequent exacerbations. Moderate- or high-risk comorbidities increased the risk of mortality (hazard ratio [HR]: 1.93, 95% confidence interval [CI]: 1.26-2.95), and this effect was magnified by the presence of P. aeruginosa (HR: 2.11, 95% CI: 1.28-3.48).

Conclusions: P. aeruginosa infection acts as a marker of disease severity as well as predictor of frequent hospitalizations. P. aeruginosa had no independent effect on all-cause mortality. P. aeruginosa combined with moderate- or high-risk comorbidities posed an increased risk of mortality. The management of comorbidities may be a critical target during the treatment of P. aeruginosa infection in bronchiectasis.KEY MESSAGE:P. aeruginosa increased the risk of frequent hospitalizations; however, it had no independent impact on all-cause mortality.P. aeruginosa combined with moderate- or high-risk comorbidities posed an increased risk of mortality.The management of comorbidities may be a critical target during the treatment of P. aeruginosa infection in bronchiectasis.

Keywords: Bronchiectasis; Pseudomonas aeruginosa; hospitalizationsexacerbations; mortality.

Figure 1.

Flow chart of patient enrolment and analysis. HRCT: high-resolution computed tomography; PA: Pseudomonas aeruginosa.

Figure 2.

Kaplan–Meier log-rank test survival curve and univariate analysis for mortality. Pseudomonas aeruginosa (PA) versus non-PA. Hazard ratio for death for PA infection was 1.26 (95% CI 0.90–1.76, p = .176) in Cox proportional hazard regression analysis.

Figure 3.

Kaplan–Meier log-rank test survival curve. Comparison between four subgroups: non-Pseudomonas aeruginosa (PA) with low-risk comorbidities; non-PA with moderate or high-risk comorbidities; PA with low-risk comorbidities; PA with moderate or high-risk comorbidities.