Changing Rates of Chronic Pseudomonas aeruginosa Infections in Cystic Fibrosis: A Population-Based Cohort Study.

Background: Chronic Pseudomonas aeruginosa lung infection is associated with significant morbidity and mortality in cystic fibrosis (CF). It is not known whether recent advances in care have affected the rates of chronic infection. We aimed to determine if the rates of developing new chronic P. aeruginosa infection among adolescents and adults with CF significantly changed over time.

Methods: The cohort consisted of individuals with CF followed in the Cystic Fibrosis Foundation Patient Registry aged ≥13 years without chronic P. aeruginosa at baseline. Multivariable regression models accounting for within-patient correlation were used to assess the change in rate of developing chronic P. aeruginosa infection between 2003 and 2012.

Results: A total of 15504 individuals were followed for a median of 5 (interquartile range, 2-9) years. The annual rates of developing new chronic P. aeruginosa decreased from 14.3% in 2003 to 6.4% in 2012. After adjusting for potential confounders, relative risk (RR) of developing chronic P. aeruginosa infection decreased significantly over time compared to 2003 (P value test of trend < .001). Compared with 2003, the RR of developing chronic P. aeruginosa infection in 2012 was 0.33 (95% confidence interval, 0.30-0.37). No significant increases in risk of chronic infections with other major CF bacterial pathogens relative to 2003 were identified.

Conclusions: Among individuals with CF, a significant decrease in the risk and rates of developing chronic P. aeruginosa infection between 2003 and 2012 was observed. Whether this decline results in changes in clinical outcomes warrants further exploration.