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. 2022 Apr 19;10(2):E379–E389. doi: 10.9778/cmajo.20210216

Table 1:

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

Note = IQR = interquartile range, SD = standard deviation.

*

Except where noted otherwise.

For the comparison between the 3 waves.