Clinical and sputum characteristics of patient groups and clinical characteristics of control subjects
| Group A (n=20) | Group B (n=16) | Group C (n=25) | Group D (n=38) | Control (n=16) | ||
| Clinical characteristics | ||||||
| Age (years) | 52 (3) | 43 (3) | 51 (3) | 51 (2) | 54 (4) | |
| Gender (M:F) | 6:14 | 3:13 | 11:14 | 20:18 | 9:7 | |
| BMI (kg/m2) | 29 (1) | 38 (1)* | 26 (1) | 28 (1) | 27 (2) | |
| Age of onset (years) | 24 (3) | 20 (4) | 28 (4) | 31 (4) | ||
| Disease duration (years) | 28 (4) | 23 (4) | 24 (4) | 20 (3) | ||
| Smoking status (%) | Never | 58 | 56 | 71 | 46 | 56 |
| Ex | 26 | 38 | 21 | 41 | 44 | |
| Current | 16 | 6 | 8 | 13 | 0 | |
| Atopy (%) | 45 | 75 | 48 | 71 | ||
| Severe exacerbations/year | 3.1 (0.7) | 3.6 (0.9) | 1.4 (0.5) | 2.1 (0.4) | ||
| JACS | 2.9 (0.2) | 2.8 (0.2) | 2.6 (0.2) | 1.7 (0.1)* | ||
| Prebronchodilator FEV1 (% predicted) | 64 (5) | 75 (6) | 75 (6) | 76 (4) | ||
| Prebronchodilator FEV1/FVC | 67 (3) | 74 (3) | 69 (3) | 68 (3) | ||
| Postbronchodilator FEV1 (% predicted) | 74 (5) | 81 (7) | 81 (5) | 80 (4) | 106 (4)* | |
| Postbronchodilator FEV1/FVC | 66 (3) | 77 (2) | 70 (3) | 70 (2) | 78 (2)† | |
| Bronchodilator response (%) | 25 (3)* | 10 (2) | 6 (2) | 3 (2) | ||
| Inhaled CS (%) | 100 | 100 | 100 | 100 | ||
| Inhaled CS dose BDP (μg/24 h) | 2066 (220) | 1943 (301) | 2071 (218) | 1761 (145) | ||
| LABA (%) | 100 | 100 | 100 | 100 | ||
| Oral prednisolone use (% of subjects) | 50 | 36 | 44 | 42 | ||
| Oral prednisolone dose (mg) | 12.8 (1.5) | 10.8 (2.4) | 10.3 (2.0) | 8.1 (0.8) | ||
| Sputum characteristics | ||||||
| Eosinophils (%) | 3.9 (1.8–13.7) | 0.3 (0.3–1.3) | 0.3 (0.3–0.4) | 6.6 (2.7–14.2)‡ | ||
| Eosinophils AUC (%) | 4.7 (3.6–11.7) | 0.9 (0.2–1.5) | 1.2 (0.3–6.7) | 9.4 (1.2–16.1)§ | ||
| Neutrophils (%) | 77 (48–87) | 83 (27–90) | 84 (43–93) | 56 (30–78) | ||
| Neutrophils AUC (%) | 71 (60–82) | 69 (56–79) | 63 (51–81) | 61 (50–75) | ||
Data expressed as mean (SEM) or median (IQR).
BDP equivalents: fluticasone 2:1, budesonide 1.25:1, mometasone 1.25:1, QVAR 2:1, ciclesonide 2.5:1.
Intergroup comparison: parametric data, one-way ANOVA with Tukey test to compare all pairs of columns *p<0.05, †p<0.05 control vs group A; non-parametric data, Kruskal–Wallis test with Dunn's multiple comparison test to compare all pairs of columns, ‡p<0.05, §p<0.05 group D vs group B.
Group A, patients with severe asthma with a concordant asthma control score and eosinophilic inflammation with a significantly greater bronchodilator response; group B, patients with severe asthma who were predominantly women with high body mass index and evidence of a high asthma control score but very little eosinophilic airway inflammation; group C, patients with severe asthma with a predominantly high asthma control score and very little eosinophilic airway inflammation; group D, patients with severe asthma with predominantly eosinophilic airway inflammation and significantly low asthma control score.
AUC, area under the time curve; BDP, beclometasone dipropionate; BMI, body mass index; CS, corticosteroid; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; JACS, Juniper Asthma Control Score; LABA, long-acting β agonist.