Long-Term Antibiotics Not Needed in CF Without Chronic P Aeruginosa

Giving long-term inhaled antibiotics to people with cystic fibrosis (CF) who do not have chronic Pseudomonas aeruginosa (PA)infection does not improve outcomes, according to study findings published in Journal of Cystic Fibrosis.

Practice guidelines recommend that people with CF receive chronic treatment with inhaled antibiotics if they are chronically infected with PA from the age of 6 years. However, many clinicians prescribe inhaled antibiotics for those with CF who do not have chronic PA infection, under the assumption that this may prevent reinfection with PA or improve outcomes of CF in others ways. In light of these practices, researchers sought to establish the prevalence of inhaled antibiotic use in people with CF without chronic PA infection. They also investigated long-term outcomes of inhaled antibiotic therapy.

The study was based on data from the European Cystic Fibrosis Patient Registry, a databank of information collected on people with CF since 2008, which now includes people from 39 European countries. A total of 7210 people with CF without chronic PA infection at baseline who were at least 6 years of age were included in the study; 37.75% (2722 of 7210) of these people were on long-term inhaled antibiotic therapy.

According to registry criteria, those considered to have chronic PA must show the following at the time of data acquisition: (1) at least 50% of respiratory samples obtained during the prior 12 months are positive for PA; and/or (2) the presence of significantly elevated bacteria-specific antibodies. Those who previously met these criteria may have also been categorized as having chronic PA, depending on whether their clinician had indicated that that their status was unchanged.

Factors linked to inhaled antibiotic use were initially evaluated via logistic regression. A model was then created for calculating a propensity score for each participant that indicated their likelihood for being treated with inhaled antibiotics. Long-term outcomes with and without the use of inhaled antibiotics were also assessed.

The investigators found that treatment with inhaled antibiotics was more common in those with a severe CF genotype, diabetes, pancreatic insufficiency, and prior infection with chronic PA (odds ratio, 3.8; 95% CI, 2.88-5.04). With respect to outcomes, the analysis indicated that use of inhaled antibiotics was not associated with a decreased risk for the acquisition of PA or other resistant pathogens, nor with improvements in lung function decline, mortality, or need for transplantation.

Study limitations include lack of randomization; a lack of data on intermittent PA, which may confound the decision regarding whether to treat with inhaled antibiotics; and bias created by registry requirements surrounding the recording of inhaled antibiotic use (ie, at least 3 months of use must occur in the same year for antibiotic use to be indicated, thus potentially underestimating treatment effects).

“[W]e found that over 32% of [people with] CF who are not chronically infected with PA are receiving long-term treatment with inhaled antibiotics,” said study authors. Further controlled studies are needed to assess how people with CF are affected by specific inhaled antibiotic regimens targeting specific pathogens or indications, said study authors.

Disclosure: One of the study authors has declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of the author’s disclosures.

Reference

Orenti A, Mei-Zahav M, Boracchi P, Lindblad A, Shteinberg M; ECFSPR Scientific Committee. Prevalence, trends and outcomes of long-term inhaled antibiotic treatment in people with cystic fibrosis without chronic Pseudomonas aeruginosa infection – a European cystic fibrosis patient registry data analysis. J Cyst Fibros. Published online August 28, 2022. doi:10.1016/j.jcf.2022.08.010