Determinants of severe asthma exacerbation risk
| Unadjusted OR (95% CI) | P value | Adjusted OR (95% CI)* | P value | |
| Follow-up duration, months | 1.03 (1.02 to 1.05) | <0.001 | 0.99 (0.97 to 1.02) | 0.438 |
| Sex | ||||
| Female | 1.00 (Ref) | – | 1.00 (Ref) | – |
| Male | 0.81 (0.58 to 1.12) | 0.205 | 1.11 (0.81 to 1.52) | 0.512 |
| Age, years | 0.99 (0.98 to 1.00) | 0.072 | 1.01 (1.00 to 1.02) | 0.202 |
| Ethnicity | ||||
| White | 1.00 (Ref) | – | 1.00 (Ref) | – |
| Other | 1.01 (0.53 to 1.91) | 0.976 | 1.25 (0.69 to 1.52) | 0.461 |
| Current tobacco smoking | ||||
| No | 1.00 (Ref) | – | 1.00 (Ref) | – |
| Yes | 1.96 (1.11 to 3.45) | 0.020 | 1.34 (0.78 to 2.31) | 0.290 |
| Educational attainment | ||||
| Postgraduate | 1.00 (Ref) | – | 1.00 (Ref) | – |
| College/university | 1.32 (0.95 to 1.83) | 0.095 | 1.05 (0.77 to 1.42) | 0.774 |
| Higher/further (A levels) | 1.57 (1.02 to 2.41) | 0.042 | 1.09 (0.72 to 1.64) | 0.688 |
| Primary/secondary | 1.22 (0.74 to 2.02) | 0.442 | 1.06 (0.66 to 1.70) | 0.820 |
| Body mass index, kg/m² | ||||
| <25 | 1.00 (Ref) | – | 1.00 (Ref) | – |
| 25–30 | 1.22 (0.87 to 1.70) | 0.253 | 1.12 (0.82 to 1.54) | 0.468 |
| ≥30 | 2.18 (1.57 to 3.03) | <0.001 | 1.36 (0.98 to 1.87) | 0.062 |
| Asthma treatment | ||||
| Reliever only† | 1.00 (Ref) | – | 1.00 (Ref) | – |
| ICS±reliever‡ | 1.51 (1.02 to 2.24) | 0.041 | 1.24 (0.84 to 1.83) | 0.299 |
| LAB±ICS or reliever§ | 3.67 (2.58 to 5.21) | <0.001 | 1.94 (1.36 to 2.78) | <0.001 |
| Monoclonal antibody¶ | 53.47 (16.39 to 174.46) | <0.001 | 7.24 (2.36 to 22.18) | 0.004 |
| Asthma exacerbation pre-enrolment** | ||||
| No | 1.00 (Ref) | – | 1.00 (Ref) | – |
| Yes | 8.75 (6.55 to 11.70) | <0.001 | 5.01 (3.67 to 6.85) | <0.001 |
| Index of multiple deprivation, quartile | ||||
| Q4 (least deprived) | 1.00 (Ref) | – | 1.00 (Ref) | – |
| Q3 | 0.96 (0.65 to 1.41) | 0.826 | 0.96 (0.66 to 1.38) | 0.807 |
| Q2 | 1.10 (0.75 to 1.63) | 0.618 | 1.04 (0.72 to 1.49) | 0.845 |
| Q1 (most deprived) | 1.35 (0.92 to 1.98) | 0.121 | 1.02 (0.71 to 1.47) | 0.900 |
| Self-reported general health | ||||
| Excellent | 1.00 (Ref) | – | 1.00 (Ref) | – |
| Very good | 1.70 (0.91 to 3.19) | 0.096 | 1.73 (0.90 to 3.31) | 0.098 |
| Good | 2.85 (1.54 to 5.28) | 0.001 | 1.99 (1.04 to 3.80) | 0.037 |
| Fair | 5.90 (3.15 to 11.03) | <0.001 | 3.17 (1.64 to 6.16) | 0.001 |
| Poor | 12.23 (6.08 to 24.61) | <0.001 | 4.57 (2.19 to 9.55) | <0.001 |
| Primary course of SARS-CoV-2 vaccination | ||||
| No | 1.00 (Ref) | – | 1.00 (Ref) | – |
| Yes | 1.35 (1.13 to 1.61) | 0.001 | 1.12 (0.84 to 1.48) | 0.466 |
| Incident COVID-19 | ||||
| No | 1.00 (Ref) | – | 1.00 (Ref) | – |
| Yes, before December 2021 | 4.09 (2.22 to 7.53) | <0.001 | 5.89 (3.45 to 10.04) | <0.001 |
| Yes, on/after December 2021 | 4.17 (2.77 to 6.27) | <0.001 | 5.69 (3.89 to 8.31) | <0.001 |
| Incident non-COVID-19 ARI | ||||
| No | 1.00 (Ref) | – | 1.00 (Ref) | – |
| Yes | 4.53 (3.72 to 5.52) | <0.001 | 5.75 (4.75 to 6.97) | <0.001 |
*Mutually adjusted for all independent variables displayed.
†Inhaled short-acting beta-agonist or anticholinergic.
‡Regular use of ICS±reliever inhaler, but no LAB or monoclonal antibody treatment.
§Regular use of LAB±-ICS or reliever inhaler, but no monoclonal antibody treatment.
¶Monoclonal antibody treatment, with or without any other treatment.
**Defined as reporting at least one asthma exacerbation requiring treatment with systemic corticosteroids and/or precipitating emergency department attendance or hospital admission in the 12 months preceding enrolment to COVIDENCE UK.
ARI, acute respiratory infection; ICS, inhaled corticosteroid; LAB, long-acting bronchodilator inhaler; Ref, referent category.