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.

The July Effect on Maternal Peripartum Complications before and after Resident Duty Hour Reform: A Population-Based Retrospective Cohort Study.

Objective To compare maternal birth complications early versus late in the academic year and to evaluate the impact of resident work hour limitation on the "July effect." Study Design We conducted a retrospective, population-based cohort study of 628,414 singleton births in Washington State from 1987 to 2012 measuring the adjusted risk of maternal peripartum complications early (July/August) versus late (April/May) in the academic year. To control for seasonal outcome variation unrelated to trainees' involvement in care as well as long-term trends in maternal complications unrelated to variation in trainees' effect on outcomes across the academic year, we employed difference-in-differences methods contrasting outcomes at teaching to nonteaching hospitals for deliveries before and after restriction of resident work hours in July 2003. Results Prior to resident work hour limitation in July 2003, women delivering early in the academic year at teaching hospitals suffered more complications (relative risk [RR] 1.05; 95% confidence interval [CI]: 1.00-1.09; p = 0.03). After July 2003, complication risk did not vary significantly across the academic year except at teaching-intensive hospitals, where July/August deliveries experienced fewer complications (RR: 0.95; 95% CI: 0.92-0.98; p = 0.001). Conclusion Women delivering at teaching hospitals early in the academic year suffered a modest but significant increase in complications before but not after resident work hour reform.