Volume 17, Number 8—August 2011
Research
Case–Control Study of Risk Factors for Hospitalization Caused by Pandemic (H1N1) 2009
Kate A. Ward, Paula J. Spokes
, and Jeremy M. McAnulty
, and Jeremy M. McAnultyTable 1
Independent risk factors for hospitalization from pandemic (H1N1) 2009 influenza, all case-patients and controls, Sydney, Australia, 2009*
| Patient characteristic |
Adjusted OR (95% CI) |
p value |
|---|---|---|
| Sex | ||
| F | Referent | |
| M |
1.8 (1.2–2.5) |
0.0017 |
| Age, y | ||
| 16–25 | 5.4 (2.5–11.4) | |
| 26–35 | 4.1 (2.0–8.3) | |
| 36–45 | 3.9 (2.0–7.6) | <0.0001 |
| 46–55 | 5.1 (2.7–9.6) | |
| 56–65 | 1.9 (1.0–2.5) | |
| >65 |
Referent |
|
| Underlying condition | ||
| Asthma, regular medication | 4.3 (2.7–6.8) | <0.0001 |
| Heart disease | 2.3 (1.2–4.1) | 0.0083 |
| Immunosuppression | 5.5 (2.8–10.9) | <0.0001 |
| Lung disease | 6.6 (3.8–11.6) | <0.0001 |
| Diabetes | 3.8 (2.2–6.5) | <0.0001 |
| Pregnancy |
22.4 (9.2–54.5) |
<0.0001 |
| Smoking status | ||
| Nonsmoker | Referent | |
| Current smoker | 2.0 (1.3–3.2) | 0.002 |
| Former smoker |
2.0 (1.3–3.0) |
|
| No. significant risk factors | ||
| 0 | Referent | |
| 1 | 3.9 (2.6–5.8) | |
| 2 | 9.3 (5.9–14.6) | <0.0001 |
| 3 | 20.4 (10.4–40.2) | |
| >4 | 80.3 (10.1–638.7) |
*OR, odds ratio; CI, confidence interval.
