TABLE 1.
Clinical characteristics of patients with asthma and healthy controls
| Asthma patients (n=154) | Healthy controls (n=28) | p-value | |
| Age (years) | 53.1 (45.0–64.9) | 56.2 (36.1–68.7) | 0.97 |
| BMI (kg·m–2) | 27.2 (24.4–30.7) | 24.9 (22.4–27.1) | 0.012 |
| Female | 86 (56) | 12 (43) | 0.288 |
| Current or ex-smoker ≥10 pack-years | 40 (26) | 4 (14) | 0.276 |
| Atopy, blood and sputum differential counts | |||
| Atopy | 88 (59) | 9 (33) | 0.024 |
| Blood eosinophil granulocytes (×103 µL−1) | 0.29 (0.14–0.49) | 0.12 (0.07–0.17) | <0.001 |
| Blood neutrophil granulocytes (×103 µL−1) | 4.32 (3.37–5.88) | 3.20 (2.53–3.59) | <0.001 |
| Sputum eosinophil granulocytes (%) | 1.8 (0.5–6.7) | 0.1 (0.0–0.5) | <0.001 |
| Sputum neutrophil granulocytes (%) | 56.0 (32.0–73.1) | 53.4 (21.4–72.8) | 0.490 |
| Blood eosinophils ≥300 µL−1 | 75 (49) | 2 (7) | <0.001 |
| Sputum eosinophils ≥2% | 65 (49) | 0 (0) | <0.001 |
| Lung function | |||
| FEV1 (z-score) | −1.53 (−2.40– −0.49) | −0.03 (−0.49–0.46) | <0.001 |
| FEV1 (% pred) | 78.55 (65.18–92.8) | 99.62 (92.26–107.68) | <0.001 |
| FEV1/FVC (z-score) | −1.73 (−2.69– −0.81) | −0.65 (−0.95– −0.12) | <0.001 |
| FEV1/FVC (% pred) | 84.95 (74.09–92.99) | 94.52 (90.95–98.94) | <0.001 |
| FEF25–75% (z-score) | −1.69 (−2.78– −0.80) | −0.43 (−0.77–0.06) | <0.001 |
| FEF25–75% (% pred) | 51.55 (30.23–75.27) | 86.05 (73.52–101.97) | <0.001 |
| FENO (ppb) | 26.0 (16.0–44.0) | 17.0 (13.0–19.8) | <0.001 |
| R5−R20 (kPa·L–1·s–1) | 0.11 (0.06–0.19) | 0.03 (0.01–0.06) | <0.001 |
| R5−R20 (% pred) | 186 (107–331) | 93 (30–125) | <0.001 |
| AX (kPa·L–1·s–1) | 0.67 (0.31–1.61) | 0.17 (0.10–0.27) | <0.001 |
| AX (% pred) | 244 (116–498) | 60 (25–107) | <0.001 |
| FRES (Hz) | 17.07 (12.68–21.29) | 9.44 (8.45–13.08) | <0.001 |
| FRES (% pred) | 134 (109–166) | 98 (80–124) | <0.001 |
Data are presented as median (interquartile range) or n (%), unless otherwise stated. BMI: body mass index; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; FEF25–75%: forced expiratory flow at 25–75% of FVC; FENO: exhaled nitric oxide fraction; R5–R20: resistance at 5 Hz−resistance at 20 Hz; AX: reactance area; FRES: resonance frequency.