Continuous alternating inhaled antibiotic therapy in CF: A single center retrospective analysis

The efficacy of inhaled antibiotics to treat chronic Pseudomonas aeruginosa pulmonary infection in patients with cystic fibrosis (CF) has been well established. Few data are available on the value of continuous alternating inhaled antibiotic therapy (CAIT), a strategy increasingly used in the management of CF.

To investigate the effect of CAIT on clinical outcome in adult CF patients treated at the University Hospital Leuven.

Patients with a documented CF diagnosis who received inhaled antibiotics between March 2010 and January 2015 were retrospectively evaluated. In patients receiving CAIT patient characteristics, recorded spirometry data and number of IV antibiotic days were collected retrospectively at fixed time intervals, from 6months before to one year after the start of the 2nd inhaled antibiotic. For patients on inhaled antibiotic monotherapy (IAMT), the same data were obtained at similar intervals during the study period.

A total of 49 of 89 patients using chronic inhaled antibiotic therapy received CAIT. Patients receiving CAIT had a lower baseline FEV₁ and were more likely to be homozygous for F508del compared to patients receiving IAMT. FEV₁ deteriorated on average by a factor of 0.904 per year (95% CI: 0.851-0.960) prior to the start of CAIT. The initiation of CAIT was associated with an average improvement in FEV₁ by a factor of 1.148 per year (95% CI: 1.068-1.236, p=0.0002). The analysis of specific types of antibiotics revealed evidence of positive effects of adding COLI to TOBI and COLI to AZLI. We found no effect of the initiation of CAIT on the number of IV antibiotic days (p=0.80).

CF patients with more advanced lung disease are more likely to receive CAIT. In this patient group, CAIT was associated with a significant improvement in FEV₁. Further data are warranted to identify the value of CAIT.