Association Between Number of Intravenous Antipseudomonal Antibiotics and Clinical Outcomes of Pediatric Cystic Fibrosis Pulmonary Exacerbations

Background. Pulmonary exacerbations (PEx) in people with cystic fibrosis (PwCF) are associated with significant morbidity. While standard PEx treatment for PwCF with Pseudomonas aeruginosa infection includes two IV antipseudomonal antibiotics, little evidence exists to recommend this approach. This study aimed to compare clinical outcomes of single versus double antipseudomonal antibiotic use for PEx treatment. Methods. Retrospective cohort study using the linked CF Foundation Patient Registry-Pediatric Health Information System dataset. PwCF were included if hospitalized between 2007 and 2018 and 6-21 years of age. Regression modeling accounting for repeated measures was used to compare lung function outcomes between single versus double IV antipseudomonal antibiotic regimens using propensity-score weighting to adjust for relevant confounding factors. Results. Among 10,660 PwCF in the dataset, we analyzed 2,578 PEx from 1,080 PwCF, of which 455 and 2,123 PEx were treated with 1 versus 2 IV antipseudomonal antibiotics, respectively. We identified no significant differences between PEx treated with 1 versus 2 IV antipseudomonal antibiotics either in change between pre- and post-PEx percent predicted forced expiratory volume in one second (ppFEV1) (-0.84%, [95% CI -2.25, 0.56]; P = 0.24), odds of returning to >= 90% of baseline ppFEV1 within 3 months following PEx (Odds Ratio 0.83, [95% CI 0.61, 1.13]; P = 0.24) or time to next PEx requiring IV antibiotics (Hazard Ratio 1.04, [95% CI 0.87, 1.24]; P = 0.69). Conclusions. Use of 2 IV antipseudomonal antibiotics for PEx treatment in young PwCF was not associated with greater improvements in measured respiratory and clinical outcomes compared to treatment with 1 IV antipseudomonal antibiotic.