Biologic population versus non-biologic population*
| No biologic therapy (n=687) | Biologic therapy (n=1524) | P value | |
| Age at first assessment | 49.1 (14.3) | 49.7 (14.3) | 0.332 |
| 18–34 | 118 (17.2%) | 257 (16.9%) | |
| 35–54 | 315 (45.9%) | 659 (43.3%) | |
| 55–79 | 251 (36.5%) | 599 (39.4%) | |
| 80+ | 3 (0.4%) | 7 (0.5%) | |
| Age at onset of symptoms | 23.6 (18.9) | 24.5 (19.2) | 0.321 |
| <12 | 230 (37.3%) | 481 (35.7%) | |
| 12–18 | 57 (9.3%) | 124 (9.2%) | |
| >18 | 329 (53.4%) | 742 (55.1%) | |
| Gender | 0.964 | ||
| Female | 428 (62.3%) | 951 (62.4%) | |
| Male | 259 (37.7%) | 573 (37.6%) | |
| Ethnicity | 0.024 | ||
| Caucasian | 514 (75.5%) | 1218 (80.6%) | |
| Non-Caucasian | 167 (24.5%) | 293 (19.4%) | |
| BMI (kg/m2) | 30.8 (7.4) | 30.9 (6.9) | 0.747 |
| Smoking status | <0.001 | ||
| Never smoked | 428 (62.7%) | 1053 (70.8%) | |
| Ex-smoker | 211 (30.9%) | 403 (27.1%) | |
| Current smoker | 44 (6.4%) | 32 (2.2%) | |
| Atopic disease | 457 (66.7%) | 912 (60.9%) | <0.001 |
| Spinal bone density (T-Score) | −0.7 (1.4) | −0.7 (1.4) | 0.912 |
| Femoral neck bone density (T-Score) | −0.5 (1.1) | −0.4 (1.1) | 0.446 |
| FEV1 (% predicted) | 67.7 (22.0) | 64.2 (20.8) | 0.001 |
| FVC (% predicted) | 83.2 (20.0) | 83.0 (19.5) | 0.814 |
| FEV1/FVC | 65.0 (14.8) | 62.7 (18.4) | 0.007 |
| Residual volume (% predicted) | 120.7 (43.7) | 136.3 (43.7) | <0.001 |
| Total lung capacity (% predicted) | 100.5 (17.6) | 105.0 (19.1) | 0.007 |
| ACQ6 Score | 3.0 (1.4) | 2.9 (1.4) | 0.060 |
| Rescue steroids in last year | 4 (2, 6) | 4 (2, 7) | 0.005 |
| Hospital admissions for asthma in last year | 0 (0, 2) | 0 (0, 1) | 0.190 |
| Invasive ventilations (ever) | 35 (7.2%) | 158 (11.0%) | <0.001 |
| Eczema | 32 (4.9%) | 30 (2.0%) | <0.001 |
| Nasal polyps | 80 (12.3%) | 273 (18.2%) | <0.001 |
| Gastro-oesophageal reflux | 166 (25.4%) | 198 (13.2%) | <0.001 |
| Depression or anxiety | 85 (13.0%) | 93 (6.2%) | <0.001 |
| Blood eosinophil count (N/109 L) | 0.30 (0.13, 0.54) | 0.36 (0.18, 0.60) | <0.001 |
| Highest blood eosinophil count (N/109 L)† | 0.50 (0.30, 0.82) | 0.70 (0.40, 1.10) | <0.001 |
| FeNO (ppb) | 36.0 (17.0, 69.0) | 41.0 (22.0, 76.5) | <0.001 |
| IgE (IU/mL) | 182 (57, 524) | 180 (60, 467) | 0.726 |
| Maintenance oral steroids | 230 (33.5%) | 906 (59.9%) | <0.001 |
| Maintenance oral steroid dose (mg) | 6 (0, 15) | 10 (8, 15) | <0.001 |
| Inhaled steroid dose (mcg, BDP equivalent) | 2000 (1600, 2000) | 2000 (1600, 2000) | 0.056 |
| LAMA | 348 (50.9%) | 806 (54.6%) | <0.001 |
| Theophylline | 177 (25.9%) | 414 (27.7%) | 0.015 |
| SABA | 644 (94.0%) | 1434 (95.7%) | 0.007 |
| Leukotriene receptor antagonist | 378 (56.2%) | 662 (45.4%) | <0.001 |
| Maintenance macrolide | 64 (9.6%) | 135 (9.3%) | 0.077 |
| Nebuliser | 154 (22.7%) | 377 (25.4%) | 0.044 |
| Prior anti-IgE therapy | 0 (0.0%) | 251 (16.8%) | <0.001 |
*Mean (SD), median (IQR) or count (%) as appropriate.
†Highest blood count is the highest recorded in available prior medical records.
ACQ, Asthma Control Questionnaire; BMI, body mass index; FeNO, fractional exhaled nitric oxide; LAMA, long-acting antimuscarinic antagonist; SABA, short acting β2-agonist.