Table I.
Clinical characteristics of asthmatic patients and healthy subjects
| Patients with severe asthma (n = 48) | Patients with mild-to-moderate asthma (n = 17) | Healthy control subjects (n = 30) | Significance (P value) | |
|---|---|---|---|---|
| Age (y) | 50.7 (9.9) | 53.0 (16.3) | 56.9 (12.5) | .09 |
| Sex (M/F) | 24/24 | 10/7 | 16/14 | .8 |
| BMI (kg/m2) | 28.8 (6.4) | 28.3 (5.2) | 28.3 (5.2) | .9 |
| BSA (m2) | 1.9 (0.2) | 1.9 (0.2) | 1.9 (0.2) | 1.0 |
| Disease duration (y) | 26.8 (16.3) | 33.2 (5.7) | x | .2 |
| Smoking status (%) | ||||
| Never | 77 | 59 | 52 | .2 |
| Exsmoker | 21 | 35 | 41 | |
| Current smoker | 2 | 6 | 7 | |
| Smoking history >10 pack years (%) | 6 | 12 | 13 | .3 |
| Atopy (%) | 67 | 82 | 18 | <.0005 |
| Aspergillus species sensitization (%) | 23 | 36 | 7 | .08 |
| Severe exacerbations/y† | 3.0 (1.0-5.3) | 1.0 (0-2.5) | x | .007 |
| Modified ACQ score (symptoms only) | 2.6 (1.3) | 1.8 (1.4) | x | .04 |
| AQLQ score | 8.3 (25.1) | 5.2 (1.4) | x | .6 |
| Prebronchodilator FEV1 (% predicted) | 69.2 (20.1) | 79.0 (23.4) | 110.9 (15.9) | <.0005ठ|
| Prebronchodilator FEV1/FVC ratio (%) | 67.9 (12.1) | 69.7 (10.3) | 78.3 (5.6) | <.0005ठ|
| Postbronchodilator FEV1 (% predicted) | 74.4 (19.2) | 81.3 (22.7) | 112.7 (17.3) | <.0005ठ|
| Postbronchodilator FEV1/FVC ratio (%) | 69.9 (11.9) | 69.8 (10.4) | 79.9 (6.0) | <.0005ठ|
| Bronchodilator response (%) | 9.6 (14.7) | 3.5 (6.8) | 1.6 (3.5) | .0007‡ |
| Midexpiratory flow (L/s) | 2.0 (1.1) | 1.8 (0.9) | 3.2 (0.9) | <.0005ठ|
| Vital capacity (L) | 3.7 (1.1) | 4.0 (0.8) | 4.2 (0.9) | .2 |
| Functional residual capacity (L) | 3.0 (1.2) | 2.9 (0.9) | 3.1 (0.9) | .9 |
| RV (L) | 2.1 (0.9) | 2.0 (0.9) | 2.2 (0.8) | .8 |
| TLC (L) | 5.8 (1.7) | 5.9 (1.4) | 6.3 (1.2) | .6 |
| RV/TLC (%) | 35.7 (12.3) | 31.2 (9.4) | 33.6 (15.3) | .7 |
| Methacholine PC20 (mg/mL)∗ | 2.0 (0.7-6.0) | 2.4 (0.8-7.3) | 24.4 (17.6-33.7) | <.0005‡§ |
| Feno (ppb)∗ | 36.1 (27.7-47.0) | 26.4 (18.6-37.5) | 27.2 (21.1-34.7) | .2 |
| Total IgE (kU/L)∗ | 179.0 (128.7-248.9) | 137.0 (68.5-273.8) | 25.5 (15.8-41.0) | <.0005‡§ |
| Inhaled CS (%) | 100 | 82 | x | .02 |
| Inhaled CS dose, BDP (μg/24 h)† | 2000 (1600-2000) | 1000 (600-2000) | x | .004 |
| LABA (%) | 94 | 71 | x | .03 |
| Oral CS (%) | 68 | 0 | x | <.0005 |
| Montelukast (%) | 32 | 0 | x | .007 |
| Theophylline (%) | 40 | 24 | x | .3 |
| Sputum eosinophils (%)∗ | 4.3 (2.5-7.5) | 2.0 (0.8-4.8) | 0.7 (0.4-.1) | <.0005‡ |
| Sputum total neutrophils × 106 (cells/g) | 2.8 (7.0) | 4.0 (5.2) | 2.9 (3.9) | .9 |
Data are expressed as means (SDs). The Pearson χ2 and Fisher exact test were used to compare ratios. Beclomethasone dipropionate equivalents are as follows: fluticasone, 2:1; budesonide, 1.25:1; mometasone, 1.25:1; QVAR, 2:1; and ciclesonide, 2.5:1.
ACS, Asthma Control Score; BDP, beclomethasone dipropionate; BMI, body mass index; CS, corticosteroid; Feno, fraction of exhaled nitric oxide; FVC, forced vital capacity; LABA, long-acting β2-agonist.
Geometric mean (95% CI).
Median (interquartile range).
Intergroup comparisons
For parametric data, 1-way ANOVA with the Tukey test to compare all pairs of columns: ‡P < .05, patients with severe asthma versus healthy control subjects; §P < .05, patients with mild-to-moderate asthma versus healthy control subjects; and ‖P < .05, patients with severe asthma versus patients with mild-to-moderate asthma.
For nonparametric data, Kruskal-Wallis test with the Dunn multiple comparison test to compare all pairs of columns: ‡P < .05, patients with severe asthma versus healthy control subjects; §P < .05, patients with mild-to-moderate asthma versus healthy control subjects; and ‖P < .05, patients with severe asthma versus patients with mild-to-moderate asthma, Mann-Whitney U test.