Methods
A database of all PwCF on ETI therapy was cross-referenced to a
bronchoscopy database to identify individuals who underwent bronchoscopy
with BAL while on ETI therapy. Procedures performed while the individual
was on intravenous antibiotics were excluded, as were procedures where
pulmonary exacerbation was the indication. Individuals were excluded
from further analysis if they did not have at least one bronchoscopy
performed while not on ETI therapy within 5 years of the index
procedure. Clinical information including demographics and CFTR
genotype, indication for bronchoscopy, as well as BAL findings including
culture data, cell count, neutrophil count and neutrophil percentage
were abstracted from the medical record. Pathogen positive cultures were
defined as growth of any potentially pathogenic organism on culture.
Statistical analysis was performed using GraphPad Prism using paired
T-tests (continuous data) or Fisher exact test (dichotomous data).
Neutrophil cells counts were log transformed prior to analysis. The
study was approved by the UNC IRB (#21-1137).