Alternating inhaled antibiotic therapy in CF: A single center analysis

Abstract

Introduction: The efficacy of inhaled antibiotics on chronic Pseudomonas aeruginosa infections in patients with cystic fibrosis (CF) has been well established. Little data are available on the value of combination inhaled therapy (CIT), a strategy frequently used in management of CF.

Objective: To investigate the effect of CIT on FEV₁ in CF patients at the University Hospital of Leuven.

Methods: Spirometry data of adult CF patients receiving CIT between Mar 2010 - Jan 2015 were collected retrospectively at fixed time points outside an exacerbation, from 6 months before to 1 year after introduction of a 2^nd inhaled antibiotic.

Results: 50 of 99 patients using chronic inhaled antibiotic therapy, received CIT. During monotherapy all patients experienced a monthly decline in FEV₁. At start of CIT mean FEV₁ was 52%. Mean duration of CIT was 59 weeks. A combination of aztreonam lysine for inhalation solution (AZLI) with colistimethate sodium dry powder inhalator (Coli DPI) was the most frequent CIT used (34%). Patients originally treated with AZLI experienced a significant improvement in FEV₁ of 0.78% per month (p= 0.05) after the addition of coli inhalation solution or DPI. Coli treated patients exhibited an average increase in FEV₁ of 0.57% per month (p=0.10) after adding tobramycin inhalation solution (TIS) or AZLI. The addition of nebulised coli to TIS was associated with a monthly increase in FEV₁% of 0.75% (p= 0.03).

Conclusion: CIT appears to be associated with a small but significant improvement in FEV₁ in CF patients under monotherapy. On the basis of this retrospective analysis we cannot determine the superiority of one particular CIT over another. Further research is warranted to identify the value of CIT.