Table 2.
Characteristics of adults hospitalized with symptoms of respiratory illness or non-localizing fever and those with study-confirmed influenza by influenza testing status.
| All patients | Research laboratory confirmed influenza by RT-PCR | |||||||
|---|---|---|---|---|---|---|---|---|
| Characteristic | All patients N = 1422 N (%) | Not tested N = 1023 N (%) | Tested N = 399 N (%) | P-value (tested vs. not tested) | All patients N = 136 N (%) | Not tested N = 59 N (%) | Tested N = 77 N (%) | P-value (tested vs. not tested) |
| Age, years (mean ± SD) | 63 ± 17 | 66 ± 15 | 58 ± 18 | <0.001 | 59 ± 19 | 56 ± 19 | 62 ± 18 | 0.028 |
| Age group, years | ||||||||
| 18–64 | 740 (52) | 480 (47) | 260 (65) | < 0.001 | 89 (65) | 32 (54) | 57 (74) | 0.016 |
| 65+ | 682 (48) | 543 (53) | 139 (35) | 47 (35) | 27 (46) | 20 (26) | ||
| Sex | ||||||||
| Female | 855 (60) | 624 (61) | 231 (58) | 0.280 | 84 (62) | 36 (61) | 48 (62) | 0.880 |
| Male | 567 (40) | 399 (39) | 168 (42) | 52 (38) | 23 (39) | 29 (38) | ||
| Race | ||||||||
| White | 1000 (70) | 730 (71) | 270 (68) | 0.220 | 83 (61) | 41 (69) | 42 (55) | 0.160 |
| Black | 376 (26) | 258 (25) | 118 (30) | 44 (32) | 14 (24) | 30 (39) | ||
| Other | 46 (3) | 35 (3) | 11 (3) | 9 (7) | 4 (7) | 5 (6) | ||
| Fever | ||||||||
| No | 671 (47) | 564 (55) | 107 (27) | < 0.001 | 45 (33) | 28 (47) | 17 (22) | 0.002 |
| Yes | 744 (52) | 453 (44) | 291 (73) | 91 (67) | 31 (53) | 60 (78) | ||
| Unknown | 7 (0) | 6 (1) | 1 (0) | 0 (0) | 0 (0) | 0 (0) | ||
| ILI | ||||||||
| No | 641 (45) | 525 (51) | 116 (29) | <0.001 | 28 (21) | 19 (32) | 9 (12) | 0.003 |
| Yes | 781 (55) | 498 (49) | 283 (71) | 108 (79) | 40 (68) | 68 (88) | ||
| High-risk | ||||||||
| Cardiac | 280 (20) | 209 (20) | 71 (18) | <0.001 | 19 (14) | 9 (15) | 10 (13) | 0.360 |
| Pulmonary | 769 (54) | 588 (57) | 181 (45) | 76 (56) | 36 (61) | 40 (52) | ||
| Other | 373 (26) | 226 (22) | 147 (37) | 41 (30) | 14 (24) | 27 (35) | ||
| Self-reported influenza vaccination status | ||||||||
| Vaccinated | 946 (67) | 704 (69) | 242 (61) | 0.005 | 66 (49) | 32 (54) | 34 (44) | 0.310 |
| Not vaccinated | 430 (30) | 284 (28) | 146 (37) | 65 (48) | 24 (41) | 41 (53) | ||
| Unknown | 46 (3) | 35 (3) | 11 (3) | 5 (4) | 3 (5) | 2 (3) | ||
| Physician ordered test | ||||||||
| Negative | 367 (26) | 0 (0) | 367 (92) | < 0.001 | 51 (38) | 0 (0) | 51 (66) | < 0.001 |
| Positive | 32 (2) | 0 (0) | 32 (8) | 26 (19) | 0 (0) | 26 (34) | ||
| Not performed | 1023 (72) | 1023 (100) | 0 (0) | 59 (43) | 59 (100) | 0 (0) | ||
| Research lab flu status | ||||||||
| Negative | 1280 (90) | 961 (94) | 319 (80) | < 0.001 | 0 (0) | 0 (0) | 0 (0) | |
| Positive | 136 (10) | 59 (6) | 77 (19) | 136 (100) | 59 (100) | 77 (100) | ||
| Indeterminate | 6 (0) | 3 (0) | 3 (1) | 0 (0) | 0 (0) | 0 (0) | ||