Treatment with azithromycin during a 5-year period was associated with reductions in the use of intravenous (IV) antibiotics and pulmonary exacerbations in children with cystic fibrosis (CF), study results published in the Annals of the American Thoracic Society suggest.

Data from the French Cystic Fibrosis database were retrospectively explored, with a focus on patients aged 7 to 40 years with CF. Only patients who initiated long-term azithromycin therapy between 2001 and 2011 were included in the retrospective review. The maximum follow-up was 7 consecutive years, including 2 years before initiation of azithromycin and 5 years after initiation of azithromycin. A total of 1065 children and 990 adults met all inclusion criteria and were enrolled in the analysis.

Researchers examined changes in forced expiratory volume in 1 second (FEV1), as well as changes in the number of IV antibiotic courses per year. At the start of treatment initiation, the data indicated a higher-than-expected mean FEV1 in children (+1.6%; P =.007) and adults (+1.3%; P =.02).

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In the following years, the mean reduction in FEV1 in children was lower vs before azithromycin initiation (mean change of the slope, 0.7%; P =.03). Based on this finding, the investigators calculated a per-year mean decrease in FEV1 of 2.2% (95% CI, 1.87-2.45) after the first year of treatment initiation. In adults, the mean decrease in FEV1 was lower vs prior to azithromycin initiation, corresponding to an estimated mean FEV1 decrease of 1.6% per year (95% CI, 1.42-1.92).

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The researchers estimated an 11% per year increase in the mean yearly number of IV antibiotic courses in children prior to long-term azithromycin treatment (risk ratio [RR], 1.11; 95% CI, 1.04-1.2). In adults, the estimated per year increase in IV antibiotic courses prior to treatment initiation was 9% (RR, 1.09; 95% CI, 1.02-1.16). In the years after treatment initiation, the mean increase in IV antibiotic courses was reduced to an estimated 3% per year (RR, 1.03; 95% CI, 1.01-1.07) in children and 4% per year (RR, 1.04; 95% CI, 1.02-1.06) in adults.

Study limitations included its retrospective and observational nature, which may have precluded linking causality between long-term azithromycin treatment with outcomes.

The researchers concluded that the benefit of early treatment would “have to be confirmed by other longitudinal prospective studies with comparisons with control groups.”


Denis A, Touzet S, Diabaté L, et al. Quantifying long-term changes in lung function and exacerbations after initiation of azithromycin in cystic fibrosis [published online October 11, 2019]. Ann Am Thorac Soc. doi:10.1513/AnnalsATS.201812-882OC