Research Article
Influenza A H1N1 Community-Acquired Pneumonia: Characteristics and Risk Factors—A Case-Control Study
Table 1
Comparison of sociodemographic characteristics of cases and controls.
| | Variable | H1N1 cases (n, %) | Controls (n, %) | value |
| | Gender | | | 0.18 | | Men | 52 (52.5) | 163 (60.4) | | Women | 47 (47.5) | 107 (39.6) | | Age (years) | | | <0.01 | | Median | 53 | 71 | | Percentile 25–75 | 44–69 | 57–82 | | Tobacco use | | | <0.01 | | Never smoker | 43 (43.4) | 116 (47.5) | | Former smoker | 22 (22.2) | 80 (32.8) | | Smoker | 22 (22.2) | 48 (19.7) | | Unknown | 12 (12.2) | 0 (0) | | Influenza vaccine | | | <0.01 | | No | 80 (80.8) | 156 (60.7) | | Yes | 18 (18.2) | 101 (39.3) | | Pneumococcal vaccine | | | <0.01 | | No | 92 (92.3) | 213 (83.2) | | Yes | 7 (7.7) | 43 (16.8) | | Charlson | | | 0.03 | | Median | 0 | 1 | | Percentile 25–75 | 0–2 | 0–2 | | CURB65 | | | <0.01 | | 0 | 27 (27.3) | 43 (15.9) | | 1 | 40 (40.4) | 61 (22.6) | | 2 | 26 (26.3) | 115 (42.6) | | 3 | 5 (5.1) | 46 (17.0) | | 4 | 0 (0) | 5 (1.9) | | 5 | 1 (1.0) | 0 (0) | | PSI score | | | 0.08 | | 1 | 18 (18.2) | 29 (10.7) | | 2 | 21 (21.2) | 38 (14.1) | | 3 | 25 (25.3) | 74 (27.4) | | 4 | 26 (26.2) | 99 (36.7) | | 5 | 9 (9.1) | 30 (11.1) |
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26 controls had missing information on tobacco use. 13 controls and 1 case had missing information on influenza vaccine. |
