Table 1.
Baseline Characteristics of Study Patients on Admission
| Characteristics | Total | Flu A | Flu B | P |
|---|---|---|---|---|
| (n = 574) | (n = 369) | (n = 205) | ||
| Age, median (IQR), y | 63.0 (50.0–76.0) | 61.0 (48.0–74.0) | 64.0 (55.0–77.0) | .0303 |
| Male gender | 300 (52.3) | 195 (52.8) | 105 (51.2) | .7086 |
| Days from illness onset to hospitalization, median (IQR) | 5.4 (1.7–9.5) | 5.9 (2.4–9.9) | 3.7 (1.6–7.7) | .0079 |
| Comorbidities | ||||
| Hypertension | 237 (41.3) | 156 (42.3) | 81 (39.5) | .5192 |
| Heart disease | 146 (25.4) | 90 (24.4) | 56 (27.3) | .4404 |
| Diabetes | 164 (28.6) | 104 (28.2) | 60 (29.3) | .7830 |
| Chronic obstructive lung disease | 57 (9.9) | 39 (10.6) | 18 (8.8) | .4924 |
| Chronic kidney disease | 41 (7.2) | 28 (7.6) | 13 (6.3) | .5727 |
| Malignancies | 88 (15.3) | 38 (10.3) | 50 (24.4) | <.0001 |
| Oral (not inhaled) glucocorticoids before admission | 45 (7.8) | 28 (7.6) | 17 (8.3) | .7635 |
| Pregnancy | 4 (0.7) | 1 (0.3) | 3 (1.5) | .1099 |
| Cerebrovascular disease | 66 (11.5) | 43 (11.7) | 23 (11.3) | .8919 |
| Chronic liver disease | 163 (28.4) | 111 (30.1) | 52 (25.4) | .2300 |
| Symptoms and signs | ||||
| Axillary temperature >39°C | 119 (20.7) | 91 (24.7) | 28 (13.7) | .0018 |
| Respiratory rate >24/min | 30 (5.8) | 26 (7.9) | 4 (2.1) | .0070 |
| Pulse ≥125 beats/min | 22 (4.0) | 18 (5.1) | 4 (2.0) | .0773 |
| Systolic blood pressure <90 mmHg | 9 (1.7) | 4 (1.2) | 5 (2.7) | .2276 |
| Laboratory findings | ||||
| White blood cell count, ×109/L | ||||
| 4–10 | 369 (64.9) | 243 (66.4) | 126 (62.1) | .0556 |
| <4 | 80 (14.1) | 42 (11.5) | 38 (18.7) | |
| >10 | 120 (21.1) | 81 (22.1) | 39 (19.2) | |
| Neutrophil count, ×109/L | 4.5 (2.9, 7.2) | 4.6 (3.2, 7.5) | 4.2 (2.7, 6.2) | .0183 |
| Lymphocyte count, ×109/L | ||||
| ≥1.5 | 196 (34.5) | 130 (35.6) | 66 (32.5) | .4558 |
| <1.5 | 372 (65.5) | 235 (64.4) | 137 (67.5) | |
| Platelet count, ×109/L | ||||
| ≥100 | 521 (91.7) | 341 (93.2) | 180 (89.1) | .0927 |
| <100 | 47 (8.3) | 25 (6.8) | 22 (10.9) | |
| Creatinine, umol/L | ||||
| ≤133 | 516 (91.3) | 329 (90.9) | 187 (92.1) | .6170 |
| >133 | 49 (8.7) | 33 (9.1) | 16 (7.9) | |
| Aspartate aminotransferase, U/L | ||||
| ≤40 | 438 (77.9) | 270 (74.8) | 168 (83.6) | .016 |
| >40 | 124 (22.1) | 91 (25.2) | 33 (16.4) | |
| Lactate dehydrogenase, U/L | ||||
| ≤245 | 293 (63.3) | 184 (61.7) | 109 (66.1) | .3562 |
| >245 | 170 (36.7) | 114 (38.3) | 56 (33.9) | |
| Creatine kinase, U/L | ||||
| ≤185 | 370 (81.0) | 230 (78.0) | 140 (86.4) | .0277 |
| >185 | 87 (19.0) | 65 (22.0) | 22 (13.6) |
Data are expressed as No. (%) or median (IQR). P values were calculated by Mann-Whitney U test or chi-square test, where appropriate.
Abbreviations: COPD, chronic obstructive pulmonary disease; IQR, interquartile range; SBP, systolic blood pressure.