Table 2.
Clinical characteristics of laboratory-confirmed influenza A and B cases (1993–2008)
| Influenza A (n = 1,404) | Influenza B (n = 445) | ||||
|---|---|---|---|---|---|
| N | % | N | % | P-value † | |
| Asthma | 141 | 10.0 | 51 | 11.5 | 0.393 |
| Any cardiovascular disease | 585 | 41.7 | 110 | 24.7 | <.001 |
| Chronic obstructive pulmonary disease | 242 | 17.2 | 45 | 10.1 | <.001 |
| Diabetes | 133 | 9.5 | 20 | 4.5 | <.001 |
| Immunosuppressed | 252 | 17.9 | 61 | 13.7 | 0.038 |
| Any chronic disease* | 625 | 44.5 | 145 | 32.6 | <.001 |
| Mean Charlson index (SD) | 1 | 1.3 | 0 | 0.9 | <.001 |
| Any hospital admissions in last 5 years | 1,046 | 74.5 | 252 | 56.6 | <.001 |
| Median hospital admission in last 5 years (IQR) | 2 | 0 - 3 | 1 | 0 - 2 | <.001 |
| Had ≥37 physician visits in last 5 years | 703 | 50.1 | 154 | 34.6 | <.001 |
| Median physician visit in last 5 years (IQR) | 37 | 0 - 73 | 0 | 0 - 47 | <.001 |
| Received the seasonal influenza vaccine | 242 | 17.2 | 64 | 14.4 | 0.158 |
| Timing of receipt of the seasonal influenza vaccine | 0.100 | ||||
| 1-13 days before index date | 10 | 0.7 | 0 | 0.0 | |
| ≥14 days before the index date | 232 | 16.5 | 64 | 14.4 | |
| Recommended receipt of the seasonal influenza vaccine | <.001 | ||||
| Not recommended | 305 | 21.7 | 187 | 42.0 | |
| Recommended and received | 218 | 15.5 | 54 | 12.1 | |
| Recommended but not received | 881 | 62.7 | 204 | 45.8 | |
| Received a pneumococcal vaccine | 508 | 36.2 | 112 | 25.2 | <.001 |
†P-values from a Chi-squared test.
*Defined as diagnosis with one of the following diseases: diabetes, chronic obstructive pulmonary disease, asthma, ischemic heart disease, chronic renal failure, or cancer (excluding non-melanoma skin cancer).