Estimated multiplicative changes in hazard for a new asthma attack obtained by hierarchical Cox regression
| Explanatory variables | Multiplicative change in hazard | 95% CI | χ2 | df | p value |
|---|---|---|---|---|---|
| Severe events | |||||
| Effect in 1–2 days after the event | 4.69 | 2.33 to 9.44 | 18.83 | 1.0 | 0.000014 |
| Effect in 3–10 days after the event | 0.81 | 0.38 to 1.75 | 0.28 | 1.0 | 0.60 |
| Fixed effects | |||||
| Sex (girl v boy) | 1.57 | 1.02 to 2.40 | 4.29 | 1.0 | 0.038 |
| Parental smoking (yes v no) | 1.13 | 0.71 to 1.79 | 0.27 | 1.0 | 0.60 |
| Severity of asthma (serious v not serious) | 1.71 | 1.07 to 2.72 | 5.05 | 1.0 | 0.03 |
| Individual random component | 73.3 | 28.6 | 0.0000087 |