Changes in use of inhaled chronic antibiotics in the European CF population: an ECFS patient registry study

Background: Improved outcomes of people with CF (pwCF) in the last decade require reconsidering prescriptions of chronic inhaled antibiotics (iAB). We compared iAB between countries with similar CF-care structures and tested for temporal trends in Pa infection and in factors associated with iAB. Methods: Data from ECFSPR 2011-2019 was extracted for UK, France, Italy, Netherlands, Belgium, Ireland, Switzerland, and Austria for non-transplanted pwCF >2-years. Multivariable generalized estimating equation modelling was used to identify factors associated with iAB. Predictors of interest included demographics, co-infections, and disease severity. Results: Prevalence (median) of chronic Pa decreased from 36 % in 2012 to 28 % in 2019 (p = 0.023) among the 19,853 included pwCF. Proportion of iAB for chronic Pa across countries increased from (median (range)) 80.8 (61.6-87.4)% in 2012 to 87.8 (77.9-94.7)% in 2019 (p = 0.02). Prescriptions for non-chronic Pa remained similar: 21.4 (13.0-48.2)% and 24.0 (15.0-42.6)% (p = 0.74). Conversion of chronic to non-chronic Pa between 2012 and 2019 occurred in 25 % on iAB and 32 % without iAB. Conversion to chronic Pa were 27 % on iAB vs. 13 % without iAB. Factors associated with iAB regardless of Pa were pancreatic insufficiency, azithromycin and mucolytics. Markers of worse disease and S. maltophilia positive cultures were associated with iAB for pwCF without chronic Pa. Over time, chronic Burkholderia infection was associated with increasing odds of iAB. Conclusions: The high iAB prescriptions for non-chronic Pa with country-to-country differences indicate ongoing need for education about antibiotics. Rates of Pa conversions highlight benefits of ongoing microbiology surveillance.