Table 2.
Association Between Demographic/Clinical Characteristics and All-Cause Mortality and ICU Admission Among Adults Hospitalized With Laboratory-confirmed Influenza in the US Influenza Hospitalization Surveillance Network, 2011–2015
| Death | ICU Admission | |||||||
|---|---|---|---|---|---|---|---|---|
| Characteristic | Death (n = 1080) | No Death (n = 34 268) | ORa | 95% CI | ICU Admission (n = 5707) | No ICU Admission (n = 29 641) | ORa | 95% CI |
| Immunocompromised, n (%) | ||||||||
| No | 945 (3.0) | 30 770 (97.0) | Ref | 5068 (16.0) | 26 647 (84.0) | Ref | ||
| Yes | 135 (3.7) | 3498 (96.3) | 1.26 | 1.05–1.51 | 639 (17.6) | 2994 (82.4) | 1.12 | 1.03–1.23 |
| Influenza season | ||||||||
| 2011–2012 | 47 (2.5) | 1810 (97.5) | Ref | 282 (15.2) | 1575 (84.8) | Ref | ||
| 2012–2013 | 264 (2.6) | 9840 (97.4) | 1.03 | .76–1.42 | 1508 (14.9) | 8596 (85.1) | 0.98 | .85–1.13 |
| 2013–2014 | 286 (3.6) | 7735 (96.4) | 1.42 | 1.04–1.95 | 1746 (21.8) | 6275 (78.2) | 1.55 | 1.36–1.78 |
| 2014–2015 | 483 (3.1) | 14 883 (96.9) | 1.25 | .92–1.69 | 2171 (14.1) | 13 195 (85.9) | 0.92 | .80–1.05 |
| Demographic characteristics, n (%) | ||||||||
| Age groups | ||||||||
| 18–49 years | 103 (1.4) | 7117 (98.6) | Ref | 1203 (16.7) | 6017 (83.3) | Ref | ||
| 50–64 years | 247 (3.1) | 7734 (96.9) | 2.21 | 1.75–2.78 | 1608 (20.1) | 6373 (79.9) | 1.26 | 1.16–1.37 |
| 65–79 years | 268 (2.8) | 9161 (97.2) | 2.02 | 1.61–2.54 | 1624 (17.2) | 7805 (82.8) | 1.04 | .96–1.13 |
| ≥80 years | 462 (4.3) | 10 256 (95.7) | 3.11 | 2.51–3.86 | 1272 (11.9) | 9446 (88.1) | 0.67 | .62–.73 |
| Gender | ||||||||
| Male | 517 (3.3) | 15 250 (96.7) | Ref | 2807 (17.8) | 12 960 (82.2) | Ref | ||
| Female | 563 (2.9) | 19 018 (97.1) | 0.87 | .77–0.99 | 2900 (14.8) | 16 681 (85.2) | 0.80 | .76–.85 |
| Race/ethnicity | ||||||||
| Nonhispanic white | 770 (3.5) | 20 967 (96.5) | Ref | 3651 (16.8) | 18 086 (83.2) | Ref | ||
| Nonhispanic black | 114 (1.8) | 6097 (98.2) | 0.51 | .42–.62 | 941 (15.2) | 5270 (84.8) | 0.89 | .82–.96 |
| Hispanic | 49 (1.9) | 2466 (98.1) | 0.54 | .40–.72 | 362 (14.4) | 2153 (85.6) | 0.83 | .74–.94 |
| Other | 56 (3.2) | 1678 (96.8) | 0.91 | .69–1.20 | 284 (16.4) | 1450 (83.6) | 0.97 | .85–1.11 |
| Unknown/missing | 91 (2.9) | 3060 (97.1) | 0.81 | .65–1.01 | 469 (14.9) | 2682 (85.1) | 0.87 | .78–.96 |
| Pre-existing medical conditions, n (%) | ||||||||
| Obesity or morbid obesity | 223 (2.9) | 7577 (97.1) | 0.92 | .79–1.06 | 1405 (18.0) | 6395 (82.0) | 1.19 | 1.11–1.27 |
| Chronic lung disease | 410 (2.9) | 13 921 (97.1) | 0.89 | .79–1.01 | 2695 (18.8) | 11 636 (81.2) | 1.39 | 1.31–1.47 |
| Cardiovascular disease | 642 (3.9) | 15 633 (96.1) | 1.75 | 1.55–1.98 | 2899 (17.8) | 13 376 (82.2) | 1.26 | 1.19–1.33 |
| Chronic metabolic disease | 470 (3.2) | 14 174 (96.6) | 1.09 | .97–1.23 | 2558 (17.5) | 12 086 (82.5) | 1.18 | 1.11–1.25 |
| Neuromuscular disorder | 86 (4.5) | 1841 (95.5) | 1.52 | 1.22–1.91 | 357 (18.5) | 1570 (81.5) | 1.19 | 1.06–1.34 |
| Neurologic disorder | 314 (4.2) | 7110 (95.8) | 1.57 | 1.37–1.79 | 1258 (16.9) | 6166 (83.1) | 1.08 | 1.01–1.15 |
| Renal disease | 296 (4.4) | 6436 (95.6) | 1.63 | 1.42–1.87 | 1182 (17.6) | 5550 (82.4) | 1.13 | 1.06–1.22 |
| Liver disease | 59 (5.2) | 1065 (94.8) | 1.80 | 1.38–2.36 | 233 (20.7) | 891 (79.3) | 1.37 | 1.19–1.59 |
| Pregnancyb | 2 (0.2) | 2 (0.2) | 0.07 | .02–.27 | 39 (4.0) | 937 (96.0) | 0.23 | .17–.32 |
| Other social factors, n (%) | ||||||||
| Smoking–former/current | 534 (3.2) | 16 394 (96.8) | 1.07 | .95–1.20 | 3171 (18.7) | 13 757 (81.3) | 1.44 | 1.36–1.53 |
| Alcohol abuse–current | 48 (3.9) | 1187 (96.1) | 1.30 | .97–1.74 | 355 (28.7) | 880 (71.3) | 2.17 | 1.91–2.46 |
| Influenza vaccine, n (%) | ||||||||
| Yes | 459 (2.8) | 16 211 (97.2) | Ref | 2420 (14.5) | 14 250 (85.5) | Ref | ||
| No | 439 (2.9) | 14 766 (97.1) | 1.05 | .92–1.20 | 2649 (17.4) | 12 556 (82.6) | 1.24 | 1.17–1.31 |
| Unknown/missing | 182 (5.2) | 3291 (94.8) | 1.95 | 1.64–2.33 | 638 (18.4) | 2835 (81.6) | 1.33 | 1.20–1.46 |
| Influenza diagnostics and treatment, n (%) | ||||||||
| Influenza type | ||||||||
| A | 934 (3.1) | 29 474 (96.9) | Ref | 4913 (16.2) | 25 495 (83.8) | Ref | ||
| B | 132 (2.8) | 4575 (97.2) | 0.91 | .76–1.10 | 747 (15.9) | 3960 (84.1) | 0.98 | .90–1.07 |
| A and B | 11 (7.7) | 131 (92.3) | 2.65 | 1.43–4.92 | 34 (23.9) | 108 (76.1) | 1.64 | 1.11–2.41 |
| Unknown | 3 (3.3) | 88 (96.7) | 1.08 | .34–3.41 | 13 (14.3) | 78 (85.7) | 0.87 | .48–1.56 |
| Antiviral treatment | ||||||||
| Yes | 858 (2.9) | 29 208 (97.1) | Ref | 5039 (16.8) | 25 027 (83.2) | Ref | ||
| No | 215 (4.1) | 4974 (95.9) | 1.47 | 1.26–1.71 | 650 (12.5) | 4539 (87.5) | 0.71 | .65–.78 |
| Unknown/missing | 7 (7.5) | 86 (92.5) | 2.77 | 1.28–6.00 | 18 (19.4) | 75 (80.6) | 1.19 | .71–2.00 |
Abbreviations: CI, confidence interval; ICU, intensive care unit; OR, odds ratio; Ref, reference.
aAll ORs are unadjusted.
bAmong women (n = 19 581).