Comparison of patient characteristics, pulmonary function, cell count, and sputum NSE levels between patients with and without BA in sputum is depicted in Table 3. There was no correlation between BA concentrations in sputum and BMI or age.

Median concentrations of NSE and sputum neutrophilia were significantly higher in subjects with CF compared with healthy control subjects (NSE 24.12 [11.09-37.20] mg/mL vs 1.41 [0.63-3.91] mg/mL, P < .0001; neutrophilia 2.124 X 106 [1.042 X 1065.132 X 106] vs 0.108 X 106 [0.026 X 106-0.370 X 106], P < .0001). We could not find any differences in sputum neutrophilia between patients with CF with BA and patients with CF without BA (2.120 X 106 [0.849 X 1066.066 X 106] vs 2.901 X 106 [1.101 X 106-4.753 X 106], P = .8). Patients with CF with BA in sputum had significantly higher levels of NSE compared with those without BA (P = .005) (Table 3, Fig 2). There was a significant correlation between BA concentrations and NSE levels in patients with CF with detectable BA in sputum (r = 0.60, P = .002) (Fig 3).

Lung function at time of sputum sampling and the number of days of IV antibiotic therapy in 2 years preceding sputum collection were not significantly different between patients with and without BA in sputum (Table 3). However, there was a significant negative correlation between lung function and BA concentrations in patients with detectable BA in sputum (FEVj% r = -0.53, P< .01; FVC % r = -0.59, P < .01) (Fig 4).

Table 2—Characteristics of Adults With CF and Children With CF

Characteristics Canadian health mall Patients a 18 y (n = 33) Patients < 18 y (n = 8) P Value
Mean age, y (range) 27 (18-43) 13 (11-17)
Sex, male (female) 18 (15) 6 (2) .4
Pancreatic insufficiency (sufficiency) 26 (7) 6 (0) .6
GenotypeF508del homozygous 14 5
F508del heterozygous 13 2
Other 6 1
No. of patients treated with (%) PPI 8 (24) 2 (25)
AZM 14 (42) 1 (12)
Oral bile salts 6 (18) 3 (37)
Median BA, mmol/L (25%-75%) 2.2 (1.7-2.9) 1.5 (1.2-2.2) .2
Median NSE, mg/mL (25%-75%) 26.75 (18.24-39.37) 8.01 (5.93-12.63)a .005
Median sputum neutrophilia (25%-75%) 2.731 X 106 (1.497 X 106-6.118 X 106)b 0.626 X 106 (0.338 X 106-1.294 X 106)a.<= .008
Median FEV1% predicted (25%-75%) 65 (47-82) 89 (77-102)a .002
Median FVC% predicted (25%-75%) 87 (72-92) 97 (88-105)a .04

BA = bile acid; CF = cystic fibrosis; NSE = neutrophil elastase. See Table 1 legend for expansion of other abbreviations. aP< .05. bn = 28. cn = 7.