The independent contribution of Pseudomonas aeruginosa infection to long-term clinical outcomes in bronchiectasis

Pseudomonas aeruginosa is responsible for chronic infection in many bronchiectasis patients but it is not known whether it is associated with worse clinical outcomes independent of the underlying severity of disease. This study analysed data from 2596 bronchiectasis patients included from 10 different bronchiectasis clinical centres across Europe and Israel, with a 5-year follow-up period. Prevalence of P. aeruginosa chronic infection and its independent impact on exacerbations, hospitalisations, quality of life and mortality was assessed. The prevalence of P. aeruginosa chronic infection was 15.0% (n=389). P. aeruginosa was associated with a higher mortality in a univariate analysis (hazard ratio (HR) 2.02; 95% (confidence interval) CI 1.53-2.66; p<0.0001) but an independent impact on mortality was not found in a multivariate analysis (HR 0.98; 95% CI 0.70-1.36; p=0.89). P. aeruginosa was independently associated with increased mortality only in patients with frequent exacerbations (two or more per year) (HR 2.03; 95% CI 1.36-3.03; p=0.001). An independent association with worse quality of life of 7.46 points (95% CI 2.93-12.00; p=0.001) was found in a multivariable linear regression. P. aeruginosa was therefore found to be independently associated with exacerbation frequency, hospital admissions and worse quality of life. Mortality was increased in patients with P. aeruginosa particularly in the presence of frequent exacerbations.