Table 1

Baseline demographic and clinical characteristics of patients with cystic fibrosis with at least one successful LCI measurement

All subjectsChildren (<18 years)AdultsP value*
n1126844
Male:female64:4838:3026:180.85
Age (IQR), years14.7 (8.6–22.2)9.2 (7.2–12.1)24.5 (21.6–29.3)
Mean FEV1 % (SD)85.3 (16.0) (n=110)87.6 (14.4)81.7 (18.8)0.054
Mean FEV1 z-score (SD)−1.2 (1.3)−1.0 (1.1)−1.5 (1.4)0.044
Mean FVC z-score−0.6 (1.1)−0.5 (1.0)−0.8 (1.2)0.107
Mean FEF25–75 z-score−1.2 (1.5)−0.9 (1.5)−1.6 (1.4)0.018
Median BMI (IQR), kg/m2z-score: 0.30 (−0.52 to 1.05)23.2 (21.2–26.5)n/a
Phe508del homozygotes, n (%)50 (45)39 (57)11 (25)0.0009
Median sweat chloride, mmol/L (IQR)99 (85–108) (n=66)100 (86–110) (n=51)87 (71–98) (n=15)0.056
Median age at diagnosis (IQR)1.0 (0.1–5.3)0.2 (0–1.5)5.0 (1.5–16.5)<0.0001
Pancreatic sufficient, n (%)40 (36)13 (19)27 (61)0.0001
Never Pseudomonas aeruginosa, n (%)45 (40)24 (35)21 (48)0.237
Previous Pseudomonas aeruginosa, n (%)17 (15)13 (19)4 (9)0.184
Intermittent Pseudomonas aeruginosa, n (%)47 (42)30 (44)17 (39)0.695
Chronic Pseudomonas aeruginosa, n (%)3 (3)1 (2)2 (5)0.560
Intermittent and chronic Staphylococcus aureus, n (%)57 (51)31 (46)26 (59)0.180
Intermittent and chronic Aspergillus, n (%)19 (17)11 (16)8 (18)0.801
Asthma, n (%)19 (17)14 (21)5 (11)0.303
Diabetes, n (%)3 (3)0 (0)3 (7)n/a
Median (IQR) LCI7.7 (6.7–8.9)7.6 (6.8–8.6)7.8 (6.5–9.3)0.973
Median (IQR) CoV LCI3.9 (2.6–6.1)3.8 (2.8–6.1)4.3 (2.8–6.0)0.710
Median (IQR) CoV FRC4.7 (2.9–7.4)4.7 (3.1–7.7)4.9 (2.7–6.8)0.551
Number of visits with LCI, median (IQR)8 (4–9)6 (4–7)10 (4–13)0.007
Test time (min), median (IQR)18.9 (15.5–22.5)16.3 (13.5–19.3)21.2 (18.6–24.3)<0.0001
  • Data are shown as mean and SD if normally distributed, otherwise as median and IQR.

  • Data are also shown for paediatric and adult populations separately.

  • Pseudomonas status relates to that at study entry and includes patients whose status was reclassified following consent based on ongoing microbiology.

  • Bold values indicate statistical significance.

  • *P value relates to comparison of adult and paediatric values and is derived from unpaired t-test for normally distributed data, Mann-Whitney U test or two-tailed Fisher’s exact test for proportions.

  • BMI, body mass index; CoV, coefficient of variation; FEF25–75, mid-expiratory flow; FRC, functional residual capacity; LCI, lung clearance index; n/a, not applicable.