Table 3.
Baseline Characteristics and In-Hospital Outcomes Among Vaccinated Versus Unvaccinated Influenza-Positive Patients, by Age Group
| Characteristic | Age 18–64 y | Age ≥65 y | ||||
|---|---|---|---|---|---|---|
| Vaccinated, No. (Column %) |
Unvaccinated, No. (Column %) |
SMDa | Vaccinated, No. (Column %) |
Unvaccinated, No. (Column %) |
SMDa | |
| Total | 161 | 500 | … | 572 | 641 | … |
| Demographic characteristics | ||||||
| Age, y | ||||||
| 18–49 | 49 (30.4) | 243 (48.6) | 0.378 | … | … | … |
| 50–64 | 112 (69.6) | 257 (51.4) | … | … | … | … |
| 65–74 | … | … | … | 173 (30.2) | 252 (39.3) | 0.191 |
| 75–84 | … | … | … | 246 (43.0) | 241 (37.6) | … |
| ≥85 | … | … | … | 153 (26.7) | 148 (23.1) | … |
| Sex | ||||||
| Male | 52 (32.3) | 221 (44.2) | 0.247 | 262 (45.8) | 287 (44.8) | 0.021 |
| Female | 109 (67.7) | 279 (55.8) | … | 310 (54.2) | 354 (55.2) | … |
| Race/Ethnicity | ||||||
| Black, NH | 21 (13.0) | 76 (15.2) | 0.210 | 32 (5.6) | 56 (8.7) | 0.174 |
| Hispanic | 30 (18.6) | 96 (19.2) | 71 (12.4) | 87 (13.6) | … | |
| Other, NHb | 27 (16.8) | 50 (10.0) | … | 51 (8.9) | 69 (10.8) | … |
| White, NH | 82 (50.9) | 272 (54.4) | … | 416 (72.7) | 423 (66.0) | … |
| Unknown | 1 (0.6) | 6 (1.2) | … | 2 (0.3) | 6 (0.9) | … |
| Clinical characteristics | ||||||
| Influenza pneumonia or disease diagnosis | ||||||
| Yes | 144 (89.4) | 478 (95.6) | 0.236 | 538 (94.1) | 605 (94.4) | 0.014 |
| No | 17 (10.6) | 22 (4.4) | … | 34 (5.9) | 36 (5.6) | … |
| Respiratory condition | ||||||
| Yes | 112 (69.6) | 340 (68.0) | 0.034 | 424 (74.1) | 462 (72.1) | 0.046 |
| No | 49 (30.4) | 160 (32.0) | … | 148 (25.9) | 179 (27.9) | … |
| Cardiological condition | ||||||
| Yes | 95 (59.0) | 237 (47.4) | 0.234 | 481 (84.1) | 516 (80.5) | 0.094 |
| No | 66 (41.0) | 263 (52.6) | … | 91 (15.9) | 125 (19.5) | … |
| Cerebrovascular condition | ||||||
| Yes | 3 (1.9) | 19 (3.8) | 0.117 | 33 (5.8) | 31 (4.8) | 0.042 |
| No | 158 (98.1) | 481 (96.2) | … | 539 (94.2) | 610 (95.2) | … |
| Neurological and/or musculoskeletal condition | ||||||
| Yes | 37 (23.0) | 99 (19.8) | 0.078 | 215 (37.6) | 253 (39.5) | 0.039 |
| No | 124 (77.0) | 401 (80.2) | … | 357 (62.4) | 388 (60.5) | … |
| Hematologic condition | ||||||
| Yes | 14 (8.7) | 28 (5.6) | 0.120 | 41 (7.2) | 42 (6.6) | 0.024 |
| No | 147 (91.3) | 472 (94.4) | … | 531 (92.8) | 599 (93.4) | … |
| Endocrine condition | ||||||
| Yes | 109 (67.7) | 268 (53.6) | 0.292 | 455 (79.5) | 479 (74.7) | 0.115 |
| No | 52 (32.3) | 232 (46.4) | … | 117 (20.5) | 162 (25.3) | … |
| Renal condition | ||||||
| Yes | 38 (23.6) | 68 (13.6) | 0.259 | 240 (42.0) | 242 (37.8) | 0.086 |
| No | 123 (76.4) | 432 (86.4) | … | 332 (58.0) | 399 (62.2) | … |
| Gastrointestinal and hepatic condition | ||||||
| Yes | 10 (6.2) | 28 (5.6) | 0.026 | 36 (6.3) | 33 (5.1) | 0.049 |
| No | 151 (93.8) | 472 (94.4) | … | 536 (93.7) | 608 (94.9) | … |
| Any immunocompromising condition | ||||||
| Yes | 39 (24.2) | 65 (13.0) | 0.291 | 102 (17.8) | 108 (16.8) | 0.026 |
| No | 122 (75.8) | 435 (87.0) | … | 470 (82.2) | 533 (83.2) | … |
| In-hospital treatment and outcomes | ||||||
| Any influenza antiviral therapy received | ||||||
| Yes | 146 (90.7) | 441 (88.2) | 0.081 | 527 (92.1) | 592 (92.4) | 0.008 |
| No | 15 (9.3) | 59 (11.8) | … | 45 (7.9) | 49 (7.6) | … |
| ICU admission during encounter | ||||||
| Yes | 21 (13.0) | 77 (15.4) | 0.068 | 67 (11.7) | 63 (9.8) | 0.061 |
| No | 140 (87.0) | 423 (84.6) | … | 505 (88.3) | 578 (90.2) | … |
| IMV | ||||||
| Yes | 4 (2.5) | 35 (7.0) | 0.214 | 25 (4.4) | 30 (4.7) | 0.015 |
| No | 157 (97.5) | 465 (93.0) | … | 547 (95.6) | 611 (95.3) | … |
| Death | ||||||
| Yes | 6 (3.7) | 12 (2.4) | 0.077 | 23 (4.0) | 17 (2.7) | 0.076 |
| No | 155 (96.3) | 488 (97.6) | … | 549 (96.0) | 624 (97.3) | … |
| Length of stay ≥5 d | ||||||
| Yes | 43 (26.7) | 119 (23.8) | 0.067 | 161 (28.1) | 174 (27.1) | 0.022 |
| No | 118 (73.3) | 381 (76.2) | … | 411 (71.9) | 467 (72.9) | … |
Abbreviations: ICU, intensive care unit; IMV, invasive mechanical ventilation; NH, non-Hispanic; SMD, standardized mean difference.
a
An absolute SMD >0.20 indicates a nonnegligible difference in variable distributions between hospitalizations for vaccinated versus unvaccinated patients.
b
Other race defined as any 1 of the following responses: Asian, Hawaiian or other Pacific Islander, American Indian or Alaska Native, other, multiple races.