Baseline characteristics of subjects in the intention-to-treat population
| Characteristic | Placebo (N=54) | Azithromycin (N=55) | p Value |
|---|---|---|---|
| Sex, n | |||
| Male | 16 (30%) | 26 (47%) | 0.077 |
| Female | 38 (70%) | 29 (53%) | |
| Age, years | |||
| Median (range), IQR | 53 (20–74), (36–60) | 53 (19–76), (46–64) | 0.097 |
| Age at onset of symptoms, years | |||
| Median (range), IQR | 17 (1–72), (6–38) | 20 (0–71), (3–40) | 0.828 |
| Asthma duration, years | |||
| Median (range) IQR | 23 (1–63), (12.8–41.3) | 27 (2–70), (11–45) | 0.263 |
| Race, n (%) of subjects | |||
| Caucasian | 54 (100%) | 55 (100%) | – |
| Body mass index* | |||
| Mean (SD) | 26.4 (5.4) | 26.5 (4.9) | 0.926 |
| Positive atopic status, n (%) of subjects† | 38 (70%) | 35 (64%) | 0.542 |
| Total IgE (IU/ml) | |||
| Median (range), IQR | 87.3 (2–4500), (25.2–702.7) | 111.3 (1–5000), (30.4–266.0) | 0.685 |
| History of nasal polyps, n (%) of subjects | 6 (11%) | 11 (20%) | 0.291 |
| Hospitalisations due to asthma in previous year, n (%) of subjects | 13 (24%) | 13 (24%) | 1.000 |
| Emergency room visits due to asthma in previous year, n (%) of subjects | 8 (15%) | 4 (7%) | 0.237 |
| Severe asthma exacerbations requiring OCS in previous year, n (%) of subjects | 47 (87%) | 49 (89%) | 0.776 |
| LRTI requiring antibiotics in previous year, n (%) of subjects | 44 (82%) | 46 (84%) | 0.805 |
| Severe asthma exacerbations and/or LRTI requiring antibiotics in previous year | |||
| N (mean) | 3.0 (1.28) | 3.4 (2.08) | 0.536 |
| FEV1 prebronchodilator (% of predicted) | |||
| Mean (SD) | 84.8 (20.7) | 80.1 (21.9) | 0.287 |
| FEV1/FVC ratio prebronchodilator | |||
| Mean (SD) | 67.8 (12.1) | 66.8 (12.3) | 0.556 |
| FEV1 postbronchodilator (% of predicted) | |||
| Mean (SD) | 89.3 (19.2) | 83.9 (21.7) | 0.184 |
| Improvement in FEV1 after BD use (%) | |||
| Mean (SD) | 6.5 (9.0) | 5.5 (7.6) | 0.959 |
| FeNO (ppb)‡ | |||
| Median (range), IQR | 17.5 (6–63), (12–27.5) | 18.0 (4–54), (14–29) | 0.519 |
| Eosinophil count in blood (×109/l) | |||
| Median (range), IQR | 186 (40–1200), (109–354) | 208 (0–1240), (100–370) | 0.901 |
| Score on ACQ-7 | |||
| Mean (SD) | 1.7 (1.0) | 1.4 (0.9) | 0.400 |
| Score on AQLQ | |||
| Mean (SD) | 5.2 (1.1) | 5.5 (0.9) | 0.287 |
| Daily dose of inhaled corticosteroid§ (µg) | |||
| Median (range) | 2000 (1000–4000) | 2000 (1000–4000) | 0.805 |
| Regular use of oral prednisolone | |||
| N (%) of subjects | 3 (6%) | 9 (16%) | 0.124 |
| Daily maintenance dose (mg) | |||
| Median (range) | 10 (2.5–17.5) | 10 (2.5–10) | 0.359 |
| Use of montelukast (LTRA) | |||
| N (%) of subjects | 26 (48%) | 29 (53%) | 0.703 |
*Body mass index is the weight in kilograms divided by the square of the height in metres.
†Atopic status based on skin prick tests; if skin prick test was not interpretable or not available, the atopic status is based on serum RAST for standard aeroallergens (house dust mite, animal dander (cat, dog), pollen (grass, tree) and Aspergillus fumigatus).
‡FeNO was measured at a flow rate of 50 ml/s and expressed as parts per billion (ppb).
§The doses of inhaled corticosteroids were converted to the equivalent dose of beclomethasone dipropionate and expressed as beclomethasone dipropionate equivalent.
ACQ, Asthma Control Questionnaire; AQLQ, Asthma Quality of Life Questionnaire; FeNO, fraction of exhaled nitric oxide; FEV1, forced expiratory volume in 1 s; LRTI, lower respiratory tract infection; LTRA, leukotriene receptor antagonist; OCS, oral corticosteroids.