Table 3. Factors associated with death in hospitalized patients according to influenza type and subtype.
| Died patients/All patients (n = 595/1726) |
DIED PATIENTS | ||||||
|---|---|---|---|---|---|---|---|
| A* n = 193 (13.0%) |
B n = 31 (12.8%) |
p value | A(H1N1)pdm09 n = 95 (13.6%) |
A(H3N2) n = 56 (14.4%) |
p value | ||
| Age (years) | |||||||
| Mean ± SD | 69.1±15.9 | 68.2±16.2 | 74.3±12.4 | 0.04 | 62.8±16.0 | 78.2±11.5 | <0.01 |
| 18–64 | 74/807 (9.2%) | 72 (37.3%) | 2 (6.5%) | <0.01 | 46 (48.4%) | 7 (12.5%) | <0.01 |
| 65–74 | 58/328 (17.7%) | 44 (22.8%) | 14 (45.2%) | 27 (28.4%) | 10 (17.9%) | ||
| ≥75 | 92/591 (15.6%) | 77 (39.9%) | 15 (48.4%) | 22 (23.2%) | 39 (69.6%) | ||
| Female | 87/743 (11.7%) | 76 (39.4%) | 11 (35.5%) | 0.68 | 34 (35.8%) | 28 (50.0%) | 0.09 |
| Male | 137/983 (13.9%) | 117 (60.6%) | 20 (64.5%) | 61 (64.2%) | 28 (50.0%) | ||
| ≥1 comorbidity | 191/1317 (14.5%) | 163 (84.5%) | 28 (90.3%) | 0.39 | 81 (85.3%) | 48 (85.7%) | 0.94 |
| No comorbidities | 33/409 (8.1%) | 30 (15.5%) | 3 (9.7%) | 14 (14.7%) | 8 (14.3%) | ||
| COPD | 67/422 (15.2%) | 56 (29.0%) | 11 (35.5%) | 0.46 | 26 (27.4%) | 20 (35.7%) | 0.28 |
| Obesity | 24/182 (13.2%) | 21 (10.9%) | 3 (9.7%) | 0.84 | 10 (10.5%) | 6 (10.7%) | 0.97 |
| Diabetes | 60/431 (13.9%) | 51 (26.4%) | 9 (29.0%) | 0.76 | 24 (25.3%) | 15 (26.8%) | 0.84 |
| Chronic renal disease | 49/236 (20.8%) | 38 (19.7%) | 11 (35.5%) | 0.04 | 15 (15.8%) | 13 (23.2%) | 0.26 |
| Immune deficiency | 77/335 (23.0%) | 64 (33.2%) | 13 (41.9%) | 0.34 | 38 (40.0%) | 14 (25.0%) | 0.06 |
| Chronic cardiovascular disease | 84/508 (16.5%) | 72 (37.3%) | 12 (38.7%) | 0.88 | 36 (37.9%) | 26 (46.4%) | 0.30 |
| Chronic liver disease | 25/113 (22.1%) | 23 (11.9%) | 2 (6.5%) | 0.37 | 12 (12.6%) | 5 (8.9%) | 0.49 |
| Onset of symptoms to hospitalization | 0.09 | 0.01 | |||||
| ≤2 days | 93/703 (13.2%) | 76 (40.0%) | 17 (56.7%) | 29 (31.5%) | 30 (53.6%) | ||
| >2 days | 127/1010 (12.6%) | 114 (60.0%) | 13 (43.3%) | 63 (68.5%) | 26 (46.4%) | ||
| Antiviral treatment (since symptom onset) | |||||||
| Mean ± SD | 6.2±6.1 | 6.3±6.2 | 5.7±5.1 | 0.69 | 5.5±4.8 | 6.9±7.0 | 0.24 |
| ≤48h symptom onset | 37/437 (8.5%) | 31 (16.7%) | 6 (20.7%) | 0.54 | 11 (12.1%) | 10 (18.5%) | 0.01 |
| >48h symptom onset | 145/1073 (13.5%) | 128 (68.8%) | 17 (58.6%) | 71 (78.0%) | 30 (55.6%) | ||
| No | 33/150 (22.0%) | 27 (14.5%) | 6 (20.7%) | 9 (9.9%) | 14 (25.9%) | ||
| Seasonal influenza vaccine | 63/449 (14.0%) | 53 (32.3%) | 10 (27.6%) | 0.59 | 18 (19.1%) | 22 (39.3%) | 0.01 |
| Pneumonia | 182/1306 (13.9%) | 162 (84.4%) | 20 (64.5%) | 0.01 | 80 (85.1%) | 46 (82.1%) | 0.63 |
| ARDS | 134/659 (20.3%) | 117 (61.6%) | 17 (54.8%) | 0.48 | 57 (61.3%) | 29 (52.7%) | 0.31 |
| Multiorgan failure | 95/176 (54.0%) | 82 (43.9%) | 13 (41.9%) | 0.84 | 44 (47.8%) | 18 (33.3%) | 0.09 |
| Hospital stay (days) | |||||||
| Mean ± SD | 14.6±14.9 | 14.4±14.9 | 15.6±15.2 | 0.67 | 15.6±16.9 | 13.6±13.0 | 0.42 |
| 0–14 days | 144/1194 (12.1%) | 124 (64.2%) | 20 (64.5%) | 0.98 | 63 (66.3%) | 35 (62.5%) | 0.63 |
| >14 days | 80/530 (15.1%) | 69 (35.8%) | 11 (35.5%) | 32 (33.7%) | 21 (37.5%) | ||
| Season | <0.01 | <0.01 | |||||
| 2010–11 | 29/169 (17.2%) | 27 (14.0%) | 2 (6.5%) | 26 (27.4%) | 0 (0.0%) | ||
| 2011–12 | 15/122 (12.3%) | 15 (7.8%) | 0 (0.0%) | 0 (0.0%) | 14 (25.0%) | ||
| 2012–13 | 16/118 (13.6%) | 5 (2.6%) | 11 (35.5%) | 4 (4.2%) | 0 (0.0%) | ||
| 2013–14 | 43/345 (12.5%) | 43 (22.3%) | 0 (0.0%) | 17 (17.9%) | 18 (32.1%) | ||
| 2014–15 | 61/425 (14.4%) | 51 (26.4%) | 10 (32.3%) | 13 (13.7%) | 22 (39.3%) | ||
| 2015–16 | 60/547 (11.0%) | 52 (26.9%) | 8 (25.8%) | 35 (36.8%) | 2 (3.6%) | ||
*Includes types A(H1N1)pdm09, A(H3N2) and 399 not subtyped influenza A virus
COPD: chronic obstructive pulmonary disease, ARDS: acute respiratory distress syndrome