Characteristics of children with asthma and healthy controls
| Infrequent episodic | Frequent episodic | Persistent | Healthy control | p value | |
|---|---|---|---|---|---|
| ICS=inhaled corticosteroid; FEV1=forced expiratory volume in 1 second; DRS=dose-response slope, % fall in FEV1/ml saline delivered; NA=not applicable. *p<0.05 v control. | |||||
| †p<0.05 v persistent asthma. | |||||
| ‡In past 12 months. | |||||
| n | 72 | 39 | 35 | 37 | |
| Mean (SD) age (years) | 11 (2.8) | 11 (3.4) | 12 (2.6) | 11 (3.1) | 0.126 |
| Sex (% male) | 70% | 56% | 68% | 43% | 0.04 |
| Current asthma symptoms, % (past 2 weeks) | |||||
| Missed school | 8% | 13% | 29% | 0% | 0.05 |
| Increased wheeze | 21% | 38% | 54% | 0% | 0.0001 |
| Night waking | 10% | 32% | 59% | 0% | 0.0001 |
| Morning waking | 9.7% | 27% | 41% | 0% | 0.0003 |
| Nights woken, median (IQR) | 1.0 (1, 1) | 1.5 (1, 7) | 2.0 (1, 6) | 0 (0) | 0.462 |
| Morning woken, median (IQR) | 1.0 (1, 1) | 5.0 (1.5, 7) | 1.0 (1.0, 1.0) | 0 (0) | 0.061 |
| Treatment (% using) | |||||
| Cromoglycate | 14% | 18% | 26% | 0 | 0.325 |
| ICS | 58% | 82% | 83% | 0 | 0.006 |
| Oral corticosteroid | 3% | 10% | 20% | 0 | 0.01 |
| Median (IQR) daily dose ICS (μg) | 0 (0–400) | 400 (0–775) | 400 (100–1000) | 0 | <0.01 |
| Mean (SD) asthma history‡ | |||||
| Duration of asthma (years) | 7.3 (3.7) | 8.8 (3.6) | 9.6 (3.3) | NA | 0.008 |
| Missed school (days) | 5.8 (4.7) | 11.1 (10.8) | 20.4 (15.8) | NA | 0.0001 |
| Exacerbations (n) | 2.2 (1.7) | 4.6 (3.4) | 7.4 (6.8) | NA | 0.0001 |
| GP visits (n/year) | 3 (4.3) | 6.2 (5.9) | 10.9 (13.0) | NA | 0.0001 |
| Admissions (n/year) | 1.0 (0.5) | 2.4 (2.1) | 2.3 (1.6) | NA | 0.164 |
| Exacerbations (days in past year) | 17.1 (32.9) | 29.4 (31.9) | 59.5 (84.9) | NA | 0.001 |
| Mean (SE) lung function | |||||
| FEV1 (% predicted) | 100.9 (1.7)† | 103.6 (2.4)† | 93.4 (2.6)* | 100 (2.1) | 0.018 |
| DRS | 1.5 (0.3) | 3.1 (1.1)* | 6.6 (2.9)* | 0.94 (0.22) | 0.001 |