Categorical analysis of steroid response in eosinophilic asthma (EA) and non-eosinophilic asthma (NEA) using predetermined cut-off points for improvements in symptoms, lung function, airway hyper-responsiveness and airway inflammation
| All | EA | NEA | p Value (EA vs NEA) | ||||
| +ve | −ve | +ve | −ve | +ve | −ve | ||
| ACQ | 61/88 (69%) | 27/88 (31%) | 48/60 (80%) | 12/60 (20) | 13/28 (46%) | 15/28 (54%) | 0.001 |
| FEV1 | 52/88 (59%) | 36/88 (41%) | 48/60 (80%) | 12/60 (20%) | 4/28 (14%) | 24/28 (86%) | <0.001 |
| PC20AMP | 48/77 (62%) | 29/77 (38%) | 36/49 (73%) | 13/49 (27%) | 12/28 (43%) | 16/28 (57%) | 0.008 |
| Feno | 53/87 (61%) | 34/87 (39%) | 44/59 (75%) | 15/59 (25%) | 9/28 (32%) | 19/28 (68%) | <0.001 |
A positive response occurred in those subjects whose change for a given end point with treatment exceeded the following cut-off points: ACQ ≥0.5 point decrease; FEV1 ≥12% increase; PC20AMP ≥2 doubling dose increase; and Feno ≥40% decrease. Results presented as proportions (%). Comparisons between EA and NEA analysed using χ2 tests. Not all subjects were able to undergo AMP challenge for safety reasons.
ACQ, Asthma Control Questionnaire; Feno, fraction of exhaled nitric oxide; FEV1, forced expiratory volume in 1 s; PC20AMP, Provocation concentration of adenosine monophosphate causing a 20% fall in FEV1.