Multivariable regression of asthma, obesity and age category as risk factors for intensive care unit admission with pH1N1 and seasonal influenza A
| Risk factor | pH1N1 | Seasonal influenza | ||||
| OR | Lower 95% CI | Upper 95% CI | OR | Lower 95% CI | Upper 95% CI | |
| Asthma* | 4.56 | 1.16 | 17.89 | 2.47 | 0.24 | 25.80 |
| Obesity | 4.18 | 0.76 | 22.95 | 1.06 | 0.20 | 5.64 |
| Age 0 to <2 years | 1.00 | 1.00 | ||||
| Age 2 to <5 years | 1.70 | 0.30 | 9.48 | 1.40 | 0.44 | 4.44 |
| Age ≥5 years | 0.89 | 0.19 | 4.07 | 0.62 | 0.19 | 1.98 |
Bold values are significantly different as defined by a p value <0.05.
↵* Asthma was also more common as a risk factor (OR 5.22, 95% CI 1.23 to 22.08) for admission to ICU in pH1N1 compared to seasonal influenza A (with age as continuous variable).
Unadjusted (univariate) ORs for pH1N1: asthma (OR 1.43, 95% CI 0.52 to 3.91), obesity (OR 3.25, 95% CI 0.81 to 19.69), age 0 to <2 years (OR 1.00), age 2 to <5 years (OR 2.18, 95% CI 0.51 to 9.26), age ≥5 years (OR 2.39, 95% CI 0.66 to 8.58). Unadjusted (univariate) ORs for seasonal influenza A: asthma (OR 0.67, 95% CI 0.08 to 5.56), obesity (OR 1.14, 95% CI 0.22 to 5.99), age 0 to <2 years (OR 1.00), age 2 to <5 years (OR 1.30, 95% CI 0.51 to 3.32), age ≥5 years (OR 0.92, 95% CI 0.36 to 2.33).
pH1N1, pandemic H1N1.