All admissions | Influenza-positive | Crude OR | Heterogeneity by strain (I2) | aOR(*) | ||||
---|---|---|---|---|---|---|---|---|
N = 10140 | N = 2895 | |||||||
Characteristic | N | N | % | Value | 95% CI | Value | 95% CI | |
Age group | ||||||||
0–1 years | 2692 | 331 | 12.3 | 1.00 | – | 79.4% | 1.00 | – |
2–4 years | 1217 | 311 | 25.6 | 2.45 | 2.06–2.92 | 75.6% | 0.86 | 0.67–1.09 |
5–17 years | 827 | 381 | 46.1 | 6.09 | 5.03–7.38 | 94.6% | 1.59 | 0.85–2.96 |
18–49 years | 2100 | 795 | 37.9 | 4.35 | 3.73–5.06 | 96.4% | 0.65 | 0.22–1.97 |
50–64 years | 735 | 195 | 26.5 | 2.58 | 2.10–3.15 | 96.6% | 0.59 | 0.25–1.39 |
65–74 years | 793 | 228 | 28.8 | 2.88 | 2.37–3.50 | 95.3% | 0.61 | 0.31–1.22 |
75–84 years | 903 | 272 | 30.1 | 3.07 | 2.55–3.71 | 96.9% | 0.50 | 0.21–1.20 |
≥ 85 years | 701 | 260 | 37.1 | 4.21 | 3.45–5.13 | 98.4% | 0.49 | 0.19–1.28 |
Sex | ||||||||
Male | 5105 | 1339 | 26,2% | 1.00 | 54.0% | 1.00 | ||
Female | 5035 | 1556 | 30,9% | 1.26 | 1.15–1.37 | 46.5% | 0.84 | 0.74–0.95 |
Smoking habits | ||||||||
Current smoker | 2270 | 542 | 23,9% | 1.00 | 81.7% | 1.00 | ||
Past smoker | 2006 | 640 | 31,9% | 1.49 | 1.30–1.71 | 88.4% | 1.04 | 0.89–1.22 |
Never smoker | 5704 | 1598 | 28,0% | 1.24 | 1.11–1.39 | 34.0% | 1.09 | 0.93–1.28 |
Consultations at the GP (last 3 months) | ||||||||
No | 3283 | 779 | 23,7% | 1.00 | 95.0% | 1.00 | ||
Yes | 5725 | 1398 | 24,4% | 1.04 | 0.94–1.15 | 92.6% | 0.91 | 0.69–1.18 |
Occupation / Social class | ||||||||
Qualified | 3810 | 1255 | 32,9% | 1.00 | 97.1% | 1.00 | ||
Skilled | 1376 | 355 | 25,8% | 0.71 | 0.62–0.81 | 81.9% | 0.83 | 0.72–0.94 |
Low or unskilled | 3411 | 591 | 17,3% | 0.43 | 0.38–0.48 | 91.5% | 0.63 | 0.50–0.78 |
Other risk factors | ||||||||
Comorbidity | 3714 | 1234 | 33,2% | 1.43 | 1.31–1.56 | 98.7% | 0.90 | 0.63–1.30 |
Cardiovascular disease | 2094 | 796 | 38,0% | 1.74 | 1.57–1.92 | 98.7% | 1.01 | 0.72–1.40 |
Chronic obstructive pulmonary disease | 1008 | 206 | 20,4% | 0.62 | 0.52–0.72 | 92.5% | 0.66 | 0.45–0.98 |
Asthma | 463 | 187 | 40,4% | 1.74 | 1.44–2.11 | 94.3% | 1.31 | 0.96–1.77 |
Immunodeficiency/organ transplant | 222 | 67 | 30,2% | 1.08 | 0.81–1.45 | 85.2% | 0.57 | 0.28–1.17 |
Diabetes | 1049 | 362 | 34,5% | 1.36 | 1.19–1.56 | 98.1% | 1.19 | 1.03–1.37 |
Chronic renal impairment | 617 | 208 | 33,7% | 1.29 | 1.09–1.54 | 89.2% | 1.06 | 0.89–1.27 |
Chronic neuromuscular disease | 426 | 192 | 45,1% | 2.13 | 1.75–2.59 | 91.7% | 1.08 | 0.75–1.56 |
Active neoplasm | 479 | 168 | 35,1% | 1.37 | 1.13–1.67 | 96.8% | 0.63 | 0.42–0.95 |
Chronic liver disease | 135 | 38 | 28,1% | 0.98 | 0.67–1.43 | 38.8% | 1.09 | 0.79–1.50 |
Autoimmune disease | 131 | 35 | 26,7% | 0.91 | 0.62–1.35 | 23.8% | 1.14 | 0.84–1.56 |
Obesity | 1457 | 374 | 25,7% | 0.92 | 0.81–1.04 | 93.3% | 0.83 | 0.69–1.00 |
Pregnancy | 942 | 483 | 51,3% | 2.96 | 2.58–3.40 | 97.6% | 3.02 | 1.59–5.76 |
Days from onset of symptoms to swabbing | ||||||||
0–2 days | 3585 | 1211 | 33,8% | 1.00 | 92.8% | 1.00 | ||
3–4 days | 3573 | 1052 | 29,4% | 0.82 | 0.74–0.90 | 36.9% | 1.05 | 0.99–1.12 |
5–7 days | 2505 | 564 | 22,5% | 0.57 | 0.51–0.64 | 83.4% | 0.82 | 0.64–1.07 |
8–9 days | 394 | 59 | 15,0% | 0.35 | 0.26–0.46 | 65.2% | 0.60 | 0.47–0.77 |