Table 3.
Baseline and demographic characteristics of the two study cohorts: patients whose inhaled corticosteroid (ICS) device was switched (switched cohort) and the matched patients whose ICS device was not switched (control cohort)
| Baseline Characteristic | Switched Cohort (n = 824) |
Control Cohort (n = 824) |
p Value For Comparison | |
| Sex* | Female, n (%) | 445 (54%) | 445 (54%) | N/A |
| Age* in yrs | Median (IQR) | 32 (15–50) | 33 (14–51) | 0.720** |
| Smoking status,* n (%) | Non-smoker | 399 (48%) | 399 (48%) | N/A |
| Smoker | 240 (29%) | 240 (29%) | ||
| Ex-smoker | 54 (7%) | 54 (7%) | ||
| Passive smoker | 20 (2%) | 20 (2%) | ||
| Data missing | 111 (13%) | 111 (13%) | ||
| Recorded rhinitis history,* n (%) | 144 (17%) | 144 (17%) | N/A | |
| Oral corticosteroid courses/yr,* n (%) | 0 | 709 (86%) | 709 (86%) | N/A |
| 1 | 76 (9%) | 76 (9%) | ||
| 2 | 20 (2%) | 20 (2%) | ||
| 3–8 | 19 (2%) | 19 (2%) | ||
| Hospitalized for asthma,* n (%) | 5 (0.6%) | 5 (0.6%) | N/A | |
| Socioeconomic quintile, n (%) | Lowest | 309 (38%) | 189 (23%) | <0.001 § |
| 2nd | 49 (6%) | 111 (13%) | ||
| 3rd | 297 (36%) | 162 (20%) | ||
| 4th | 50 (6%) | 167 (20%) | ||
| Highest | 119 (14%) | 192 (23%) | ||
| SABA daily dose, † median (IQR) | 0.55 (0–1.64) | 0.82 (0.27–1.64) | <0.001** | |
| Asthma consultations/yr | Median (IQR) | 0 (0–1) | 1 (0–2) | |
| Range | 0–9 | 0–14 | ||
| Asthma consultation rate, n (%) | 0 | 524 (64%) | 406 (49%) | <0.001** |
| 1 | 167 (20%) | 212 (26%) | ||
| 2 | 73 (9%) | 103 (13%) | ||
| ≥ 3 | 60 (7%) | 103 (13%) | ||
| Recorded gastroesophageal disease, n (%) | 45 (5%) | 62 (8%) | 0.089 § | |
| Recorded cardiovascular disease, n (%) | 33 (4%) | 48 (6%) | 0.087 § | |
| Daily dose of ICS on index day, ‡ median (IQR) | 400 μg (400–800) | 400 μg (400–800) | 0.137** |
IQR = interquartile range; N/A = not applicable (because matching criterion); SABA = short-acting β-agonist
*Matching criterion (number of oral corticosteroid courses and hospitalizations for asthma were during the year before the index date).
†One dose of SABA was defined as salbutamol 200 μg or terbutaline 500 μg.
‡Dose equivalents for beclomethasone dipropionate, budesonide, fluticasone propionate, BDP in solution (QVAR®, Teva UK), and mometasone were in a ratio of 1:1:2:2:2, respectively.
§χ2 test, **Mann-Whitney