Potentially modifiable risk factors for hospital admission
| Asthma admissions (AA) | Stable asthma (SA) | Inpatient control (IC) | Odds ratio (95% CI)* | p value* | |
|---|---|---|---|---|---|
| IMD, index of multiple deprivation; ETS, environmental tobacco smoke; ICS, inhaled corticosteroid. | |||||
| *Comparisons of groups (AA v SA; AA v IC): conditional logistic regression. | |||||
| †Frequency of respiratory pathogen detected in nasal washing sample by PCR technique. | |||||
| ‡Der p 1 level in child’s mattress. | |||||
| §Fel d 1 and Can f 1 levels, lounge floor. | |||||
| ¶Proportion of subjects sensitised (assessed by skin prick testing) and exposed to high levels of the sensitising allergen (>2 μg Der p 1/g dust, >8 μg Fel d 1/g dust, >10 μg Can f 1/g dust, average pollen count high or very high on 7 days preceding admission). | |||||
| **Proportion of subjects sensitised (assessed by spin prick testing) and exposed to high levels of the sensitising allergen and having a respiratory pathogen detected in nasal washing sample by PCR technique. | |||||
| IMD, geometric mean (range) | 5284 (67–30142) | 5029 (256–32230) | 6423 (188–32308) | AA v SA: 1.0 (0.8 to 1.3) | 0.83 |
| AA v IC: 0.9 (0.7 to 1.1) | 0.38 | ||||
| ETS exposure | |||||
| Maternal smoking | 29 (34.5%) | 35 (41.7%) | 32 (38.1%) | AA v SA: 0.7 (0.4 to 1.4) | 0.32 |
| AA v IC: 0.9 (0.4 to 1.6) | 0.62 | ||||
| Paternal smoking | 31 (36.9%) | 28 (33.3%) | 28 (33.3%) | AA v SA: 1.2 (0.6 to 2.3) | 0.61 |
| AA v IC: 1.1 (0.6 to 2.1) | 0.66 | ||||
| Pet ownership | |||||
| Dog owners | 20 (23.8%) | 23 (27.4%) | 28 (33.3%) | AA v SA: 0.8 (0.4 to 1.7) | 0.56 |
| AA v IC: 0.6 (0.3 to 1.2) | 0.17 | ||||
| Cat owners | 15 (17.9%) | 21 (25%) | 21 (25%) | AA v SA: 0.7 (0.3 to 1.4) | 0.26 |
| AA v IC: 0.7 (0.3 to 1.4) | 0.26 | ||||
| Housing conditions | |||||
| Central heating | 82 (97.6%) | 82 (97.6%) | 80 (95.2%) | AA v SA: 1.0 (0.1 to 7.1) | 1.0 |
| AA v IC: 2.0 (0.4 to 10.9) | 0.42 | ||||
| Double glazing | 41 (48.8%) | 32 (38.1%) | 34 (40.5%) | AA v SA: 1.6 (0.8 to 3.2) | 0.14 |
| AA v IC: 1.5 (0.8 to 2.8) | 0.25 | ||||
| Own bedroom | 44 (52.4%) | 52 (61.9%) | 56 (66.7%) | AA v SA: 1.5 (0.8 to 2.8) | 0.21 |
| AA v IC: 1.8 (1.0 to 3.2) | 0.07 | ||||
| Own bed | 80 (95.2%) | 79 (94.0%) | 82 (97.6%) | AA v SA: 1.3 (0.3 to 6.0) | 0.71 |
| AA v IC: 0.5 (0.1 to 2.7) | 0.42 | ||||
| Condensation on bedroom window | 47 (56.0%) | 46 (54.8%) | 46 (54.8%) | AA v SA: 1.1 (0.6 to 2.0) | 0.87 |
| AA v IC: 1.0 (0.6 to 1.9) | 0.88 | ||||
| Damp/mould in bedroom | 4 (4.8%) | 4 (4.8%) | 1 (1.2%) | AA v SA: 1.0 (0.3 to 4.0) | 1.0 |
| AA v IC: 4.0 (0.5 to 35.8) | 0.22 | ||||
| Indication of asthma severity | |||||
| On regular ICS | 52 (61.9%) | 71 (84.5%) | 0 (0%) | AA v SA 0.24 (0.10 to 0.59) | 0.002 |
| AA v IC: not defined | – | ||||
| On additional controller | 11 (13.1%) | 20 (23.8%) | 0 (0%) | AA v SA: 0.47 (0.20 to 1.1) | 0.08 |
| AA v IC: not defined | |||||
| Daily wheeze symptoms | 12 (14.3%) | 13 (15.5%) | 0 (0%) | AA v SA: 0.92 (0.40 to 2.1) | 0.84 |
| AA v IC: not defined | |||||
| Virus detection† | |||||
| Any respiratory pathogen | 37 (44%) | 15 (17.9%) | 14 (16.7%) | AA v SA: 5.4 (2.1 to 14.0) | 0.001 |
| AA v IC: 4.3 (1.9 to 9.8) | 0.001 | ||||
| Rhinovirus | 30 (35.7%) | 8 (9.5%) | 6 (7.1%) | AA v SA: 8.3 (2.5 to 27.6) | 0.001 |
| AA v IC: 7.0 (2.5 to 19.9) | <0.001 | ||||
| Exposure to allergens | |||||
| Der p 1, μg/g, GM (range)‡ | 3.83 (0.05–1250) | 2.96 (0.05–98) | 4.73 (0.05–190) | AA v SA:1.3 (0.9 to 1.2) | 0.44 |
| AA v IC: 1.0 (0.9 to 1.1) | 0.54 | ||||
| Fel d 1, μg/g, GM (range)§ | 1.06 (0.05–1950) | 2.05 (0.05–1080) | 1.38 (0.05–1140) | AA v SA: 0.9 (0.8 to 1.0) | 0.13 |
| AA v IC: 1.0 (0.9 to 1.1) | 0.47 | ||||
| Can f 1, μg/g, GM (range)§ | 2.23 (0.05–3450) | 2.18 (0.05–720) | 3.44 (0.05–1650) | AA v SA: 1.0 (0.9 to 1.1) | 0.83 |
| AA v IC: 0.9 (0.8 to 1.1) | 0.28 | ||||
| Exposed to any allergen | 76/82 (92.7%) | 75/84 (89.3%) | 79/84 (94.0%) | AA v SA: 1.6 (0.5 to 4.9) | 0.41 |
| AA v IC: 0.7 (0.2 to 2.4) | 0.53 | ||||
| Sensitisation and exposure to allergens | |||||
| Any allergen | 62/82 (75.6%) | 39/82 (47.6%) | 23/82 (28.0%) | AA v SA: 2.9 (1.5 to 5.6) | 0.001 |
| AA v IC: 10.8 (3.9 to 29.9) | <0.001 | ||||
| Dust mite | 47/82 (57.3%) | 35/82 (42.7%) | 20/82 (24.4%) | AA v SA: 1.6 (0.9 to 2.9) | 0.09 |
| AA v IC: 3.7 (1.8 to 7.4) | <0.001 | ||||
| Cat | 9/82 (11.0%) | 9/82 (11.0%) | 0/82 (0%) | AA v SA: 1.0 (0.4 to 2.7) | 1.0 |
| AA v IC: not defined | |||||
| Dog | 10/82 (12.2%) | 4/82 (4.9%) | 1/82 (1.2%) | AA v SA: 2.5 (0.8 to 8.0) | 0.12 |
| AA v IC: 10.0 (1.3 to 78.0) | 0.028 | ||||
| Pollen | 14/84 (16.7%) | 4/82 (4.9%) | 3/82 (3.7%) | AA v SA: 6.0 (1.3 to 27.0) | 0.019 |
| AA v IC: not defined | |||||
| Sensitisation, exposure and respiratory pathogen detection | |||||
| Any allergen and any pathogen** | 29/82 (35.4%) | 6/82 (7.3%) | 2/82 (2.4%) | AA v SA: 8.7 (2.6 to 28.6) | <0.001 |
| AA v IC: 28.0 (3.8 to 206) | 0.001 | ||||
| Any allergen and rhinovirus | 24/82 (29.3%) | 2/82 (2.4%) | 1/82 (1.2%) | AA v SA: 23.0 (3.1 to 170) | 0.002 |
| AA v IC: 24.0 (3.2 to 177) | 0.002 | ||||