TABLE 3

Characteristics at first exacerbation overall# and by longitudinal blood eosinophil groups over 12 months

Overall cohortRarely eosinophilicIntermittently eosinophilicPredominantly eosinophilicp-valueƒ
Patients108261348
Continuous variables
 White blood cells count ×109 L–18.00 (3.53) (n=102)8.70 (4.25) (n=25)8.95 (2.55) (n=12)7.30 (3.23) (n=48)0.349
 Blood eosinophils count ×109 L–10.20 (0.20) (n=102)0.10 (0.15) (n=25)0.15 (0.10) (n=12)0.30 (0.27) (n=48)<0.001
 Blood eosinophils %2.07 (2.78) (n=102)1.19 (1.74) (n=25)1.92 (0.88) (n=12)3.39 (4.40) (n=48)<0.001
 Blood neutrophils count ×109 L–15.30 (3.20) (n=102)5.60 (4.05) (n=25)5.55 (2.57) (n=12)4.45 (2.98) (n=48)0.045
 Fibrinogen g·L–15.10 (1.40) (n=103)4.80 (1.80) (n=25)5.50 (2.25) (n=12)5.10 (1.60) (n=46)0.135
 C-reactive protein mg·L–18.00 (14.0) (n=103)7.00 (12.5) (n=25)26.5 (49.8) (n=12)7.00 (13.0) (n=47)0.087
 Sputum eosinophils %1.20 (2.38) (n=61)0.62 (2.29) (n=15)1.40 (3.23) (n=9)1.48 (3.56) (n=28)0.273
 Sputum neutrophils %74.0 (47.1) (n=61)76.8 (51.6) (n=15)86.6 (40.3) (n=9)74.1 (52.3) (n=28)0.616
 FEV1 % pred42.7 (21.2) (n=97)47.3 (30.0) (n=22)41.5 (17.5) (n=12)41.7 (20.0) (n=44)0.395
 CAT score21.0 (11.0) (n=106)22.0 (12.0) (n=26)22.0 (17.0) (n=13)19.0 (8.00) (n=47)0.915
 EXACT-PRO score41.0 (11.0) (n=97)43.0 (13.0) (n=23)40.0 (10.0) (n=12)39.5 (7.00) (n=44)0.142
Categorical variables
 Bacteria present+
  Yes60 (61)19 (86)6 (55)27 (57)0.044
  No38 (39)3 (14)5 (45)20 (43)
 Virus present§
  Yes40 (43)12 (55)4 (40)14 (33)0.235
  No53 (57)10 (45)6 (60)28 (67)
 Sputum eosinophils >3%
  Yes23 (30)2 (11)0 (0)17 (47)0.004
  No54 (70)16 (89)7 (100)19 (53)
 Blood eosinophils ≥2%
  Yes73 (68)7 (28)7 (54)47 (98)<0.001
  No34 (32)18 (72)6 (46)1 (2)

Data are presented as n for patient numbers, median (interquartile range) for continuous variables or n (%) for categorical variables, unless otherwise stated. FEV1: forced expiratory volume in 1 s; CAT: COPD Assessment Test; #: n=108; : n=87; +: sputum sampling, measured by culture sputum sampling, measured by culture (includes Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae, Staphylococcus aureus and Pseudomonas aeruginosa); §: sputum sampling, measured by PCR (includes adenovirus, enterovirus, influenza, coronavirus, metapneumovirus, bocavirus, parainfluenza, respiratory syncytial virus and rhinovirus); ƒ: test for differences between the three longitudinal eosinophil groups (Kruskal–Wallis test for continuous variables; Chi-squared test for categorical variables).