RATIONALE:

Eradication and suppression of Pseudomonas aeruginosa is a key priority in national guidelines for bronchiectasis, and is a major focus of drug development and clinical trials. An accurate estimation of the clinical impact of P. aeruginosa in bronchiectasis is, therefore, essential.

METHODS:

Data from 21 observational cohort studies comparing patients with P. aeruginosa colonisation to those without were pooled by random effects meta-analysis with data collected for key longitudinal clinical outcomes of mortality, hospital admissions, exacerbations and lung function decline along with cross sectional outcomes such as quality of life.

MEASUREMENTS AND MAIN RESULTS:

Studies included 3683 patients. P. aeruginosa was associated with a highly significant and consistent increase in all markers of disease severity including mortality (odds ratio (OR) 2.95, 95% CI 1.98-4.40; p<0.0001), hospital admissions (OR 6.57, 95% CI 3.19-13.51; p<0.0001) and exacerbations (mean difference 0.97 per year, 95% CI 0.64-1.30; p<0.0001). Patients with P. aeruginosa also had worse quality of life using the St Georges Respiratory Questionnaire (mean difference 18.2 points, 95% CI 14.7-21.8; p<0.0001). There were also large differences in lung function and radiological severity. Definitions of colonisation were inconsistent but findings were robust irrespective of the definition used.

CONCLUSION:

P. aeruginosa is associated with an approximate 3-fold increased risk of death and an increase in hospital admissions and exacerbations in adult bronchiectasis.