Table 1. .
Number (Percentage) of Hospitalized Influenza Patients With and Without Fever According to Virus Type, Age, Sex, Comorbid Conditions, and Features of Clinical Presentation
| Total n = 578 |
Fever n = 359 |
No Fever n = 219 |
P Value | |
|---|---|---|---|---|
| Virus | ||||
| Influenza A | 457 | 301 (65.9) | 156 (34.1) | <.001 |
| Influenza B | 121 | 58 (47.9) | 63 (52.1) | |
| Age | ||||
| Age <65 y | 275 | 206 (74.9) | 69 (25.1) | <.001 |
| Age 65–80 y | 157 | 81 (51.6) | 76 (48.4) | |
| Age >80 y | 146 | 72 (49.3) | 74 (50.7) | |
| Sex | ||||
| Male | 284 | 189 (66.5) | 95 (33.5) | .038 |
| Female | 294 | 170 (57.8) | 124 (42.2) | |
| Charlson Comorbidity Index score | ||||
| CCI 0 | 337 | 231 (68.5) | 106 (31.5) | <.001 |
| CCI 1–2 | 187 | 103 (55.1) | 84 (44.9) | |
| CCI >2 | 54 | 25 (46.3) | 29 (53.7) | |
| Comorbiditiesa | ||||
| Respiratory disease | 181 | 91 (50.3) | 90 (49.7) | <.001 |
| Diabetes | 151 | 86 (57.0) | 65 (43.0) | .155 |
| Malignancy | 58 | 31 (53.4) | 27 (46.6) | .197 |
| Liver disease | 22 | 13 (59.1) | 9 (40.9) | .824 |
| Cardiac disease | 181 | 100 (55.2) | 81 (44.8) | .028 |
| Neurological disease | 111 | 61 (55.0) | 50 (45.0) | .105 |
| Renal disease | 75 | 39 (52.0) | 36 (48.0) | .071 |
| Immunosuppression | 94 | 55 (58.5) | 39 (41.5) | .503 |
| Pregnant | 5 | 5 (100) | 0 (0) | .162 |
| Current smoker | 66 | 42 (63.6) | 24 (36.4) | .891 |
| Risk factors for complications | 407 | 234 (57.5) | 173 (42.5) | .001 |
| Presenting features | ||||
| Respiratory illness | 506 | 324 (64.0) | 182 (36.0) | .017 |
| Nonrespiratory illness | 72 | 35 (48.6) | 37 (51.4) | |
| Symptom duration 0–2 d | 224 | 162 (72.3) | 62 (27.7) | <.001 |
| Symptom duration >2 d | 354 | 197 (55.6) | 157 (44.4) | |
| Chest x-ray consolidationb | 87 | 57 (65.5) | 30 (34.5) | .555 |
Data are presented as No. (%).
Abbreviations: CCI, Charlson Comorbidity Index; ICD-10, International Classification of Diseases, Tenth Revision.
aComorbidities were defined as present if captured by the FluCAN standard collection instrument [8] or ICD-10 coding algorithms for Charlson Comorbidity Index score [9].
bBased on formal radiologist report of imaging.