Longitudinal changes and regional variation of incident infection rates at cystic fibrosis centers, United States 2010-2016.

Background: Multiple factors affect incident infection rates (IIR) for Pseudomonas aeruginosa (PA) and methicillin resistant Staphylococcus aureus (MRSA) at CF care centers. We assessed changes in IIR across CF centers temporally associated with the 2013 Infection/Prevention & Control guidelines controlling for center-specific factors.

Methods: Using the CF Foundation Patient Registry we defined and measured changes in IIR between 2010-2012 and 2014-2016. Data were compared to non-CF rates of MRSA and resistant PA in geographically similar regions. Characteristics of each CF center (n centers: Adult 54 in 2010 to 82 in 2016. Pediatric ∼106) and their respective population were evaluated for associations with IIR and with changes in IIR between the study periods.

Results: Across the years 35613 patients were included. Incident-infection rates for PA (mean 19.2±0.04% Pediatric, 21.2±0.07% Adult centers) were higher than for MRSA (mean 9.4±0.03% Pediatric, 7.8±0.03% Adult). The IIR decreased for MRSA (-1.54±0.54%, p<0.001) and PA (-4.77±0.63%, p<0.001) at Pediatric but only for PA (-3.20±1.31, p=0.02) at Adult centers. Except for Adult CF, MRSA rates (CF and non-CF) were highest in the South. In 2014-2016, private insurance and a higher proportion of LatinX patients at a center were associated with lower MRSA IIR while larger center size, higher proportion of LatinX, and lower mean center-wide lung function were associated with higher PA IIR. Higher IIR in 2010-2012, were predictive of a more pronounced decrease in IIR in 2014-2016 for MRSA and PA (p<0.001). Different factors indicative of lower social status (smoking, insurance, education) in 2010-2012 predicted decreases in MRSA or PA IIR.

Conclusion: Comparisons of IIR across U.S. CF centers should consider location, ethnic background and socio-economic variables of a center's population.