Baseline characteristics of patients admitted to hospital with acute COVID-19, overall and in pandemic waves 1, 2 and 3
| Characteristic | No. (%) of patients* | p value† | |||
|---|---|---|---|---|---|
| Overall n = 1337 | Wave 1 n = 520 | Wave 2 n = 572 | Wave 3 n = 245 | ||
| Admission date | – | ||||
| March–May 2020 | 429 (32.1) | 429 (82.5) | – | – | |
| June–August 2020 | 34 (2.5) | 34 (6.5) | – | – | |
| September–November 2020 | 276 (20.6) | 57 (11.0) | 219 (38.3) | – | |
| December 2020–February 2021 | 386 (28.9) | – | 353 (61.7) | 33 (13.5) | |
| March–April 2021 | 212 (15.9) | – | – | 212 (86.5) | |
| SARS-CoV-2 confirmed status | < 0.001 | ||||
| Positive on screening test | 82 (6.1) | 67 (12.9) | 13 (2.3) | 2 (0.8) | |
| Positive on definitive test | 1255 (93.9) | 453 (87.1) | 559 (97.7) | 243 (99.2) | |
| Positive for other pathogen | 11 (0.8) | 9 (1.7) | 2 (0.3) | 0 (0.0) | 0.02 |
| Sex | 0.3 | ||||
| Male | 791 (59.2) | 293 (56.5) | 348 (60.8) | 150 (61.2) | |
| Female | 545 (40.8) | 226 (43.5) | 224 (39.2) | 95 (38.8) | |
| Unknown | 1 (0.1) | 1 (0.2) | 0 (0.0) | 0 (0.0) | |
| Age, mean ± SD, yr (range) | 67.0 ± 17.1 (20–103) | 70.2 ± 16.3 (23–103) | 65.8 ± 17.3 (20–100) | 63.3 ± 17.1 (23–101) | < 0.001 |
| Received COVID-19 vaccine before admission | 24 (1.8) | 0 (0.0 ) | 3 (0.5) | 21 (8.6) | < 0.001 |
| Admitted to intensive care unit on hospital admission day | 218 (16.3) | 104 (20.0) | 83 (14.5) | 31 (12.8) | 0.01 |
| Organ support on day of admission | |||||
| Invasive mechanical ventilation | 102 (7.6) | 55 (10.6) | 34 (5.9) | 13 (5.3) | 0.005 |
| Renal replacement therapy or dialysis | 18/1320 (1.4) | 8/511 (1.6) | 7/567 (1.2) | 3/242 (1.2) | 0.9 |
| Vasopressor | 81 (6.1) | 35 (6.7) | 33 (5.8) | 13 (5.3) | 0.7 |
| Temperature, mean ± SD, °C | 37.5 ± 0.9 n = 1306 | 37.5 ± 0.9 n = 501 | 37.4 ± 0.9 n = 563 | 37.4 ± 0.8 n = 242 | 0.1 |
| Heart rate, mean ± SD, beats/min | 94.2 ± 20.3 n = 1325 | 91.4 ± 20.6 n = 514 | 95.5 ± 20.3 n = 569 | 97.4 ± 19.1 n = 242 | < 0.001 |
| Respiratory rate, mean ± SD, breaths/min | 24.0 ± 7.3 n = 1313 | 22.9 ± 6.4 n = 505 | 24.9 ± 7.9 n = 567 | 24.2 ± 7.5 n = 241 | < 0.001 |
| Systolic blood pressure, mean ± SD, mm Hg | 129.4 ± 22.7 n = 1328 | 128.8 ± 22.9 n = 518 | 130.6 ± 23.4 n = 567 | 128.0 ± 20.5 n = 243 | 0.2 |
| Diastolic blood pressure, mean ± SD, mm Hg | 73.8 ± 12.6 n = 1312 | 73.7 ± 11.9 n = 517 | 74.4 ± 13.2 n = 558 | 72.5 ± 12.5 n = 237 | 0.2 |
| Oxygen saturation level, mean ± SD, % | 91.9 ± 7.2 n = 1320 | 93.5 ± 4.2 n = 507 | 90.8 ± 8.6 n = 570 | 91.1 ± 7.9 n = 243 | < 0.001 |
| Required oxygen therapy | 436/1290 (33.8) | 186/516 (36.0) | 174/541 (32.2) | 76/233 (32.6) | 0.4 |
| Leucocyte count, median (IQR), × 103/μL | 6.6 (4.9–9.0) n = 1310 | 6.5 (4.9–8.6) n = 503 | 7.0 (5.1–9.2) n = 566 | 6.4 (4.7–9.1) n = 241 | 0.09 |
| Hemoglobin level, median (IQR), g/L | 132.0 (117.0–145.0) n = 1311 | 130.0 (118.0–145.0) n = 505 | 132.0 (117.0–145.0) n = 565 | 134.0 (119.0–145.0) n = 241 | 0.5 |
| Creatinine level, median (IQR), μmol/L | 85.0 (69.0–115.0) n = 1309 | 84.0 (68.0–114.0) n = 510 | 87.0 (70.0–121.0) n = 561 | 82.0 (66.0–107.0) n = 238 | 0.04 |