Influenza A H1N1 Community-Acquired Pneumonia: Characteristics and Risk Factors—A Case-Control Study
Table 3
Multivariate analysis calculating the risk of being a H1N1 CAP case or control.
Variable
Crude OR
95% CI
Adjusted OR
95% CI
Gender
Male
1
—
1
—
Female
1.38
0.87–2.19
1.21
0.65–2.27
Age (years)
<55
1
—
1
—
55–74
0.46
0.27–0.80
1.80
0.82–3.94
≥75
0.16
0.09–0.31
0.80
0.32–2.02
Influenza vaccine
No
1
—
1
—
Yes
0.35
0.2–0.61
0.80
0.29–2.17
Pneumococcal vaccine
No
1
—
1
—
Yes
0.38
0.16–0.87
1.08
0.30–3.82
CURB65
0
1
—
1
1.04
0.56–1.95
2
0.36
0.19–0.68
3
0.17
0.06–0.49
4
n/a
n/a
5
n/a
n/a
PSI score
1
1
—
2
0.89
0.40–1.97
3
0.54
0.26–1.14
4
0.42
0.20–0.88
5
0.48
0.19–1.25
Leukocytes (cell/mm3)
≤500
1
—
1
—
>500
0.20
0.12–0.35
0.42
0.21–0.81
AST (IU/L)
≤24
1
—
1
—
>25
4.74
2.75–8.19
2.60
1.32–5.09
Arthromyalgias
No
1
—
1
—
Yes
4.12
2.4–7.10
2.96
1.40–6.26
Chest X-ray presentation
Lobar
1
—
1
—
Bilobar
0.22
0.03–1.69
0.26
0.03–2.18
Bilateral
8.95
4.97–14.36
5.30
2.69–10.40
AST: aspartate aminotransferase; CURB65: pneumonia severity score calculator 65; PSI score: pneumonia severity index score. The variables which had a significant result are given in bold. CURB65 and PSI index were excluded from multivariate analysis. All other variables were included as shown in crude analysis. Adjusted OR includes gender, age, influenza vaccine, pneumococcal vaccine, leukocytes, AST, arthromyalgias, and chest X-ray presentation.
