Table 1 Characteristics of the cohorts
Variable | All COVID-19 (n = 2385) | Wild-type (n = 1421) | Alpha (n = 551) | Delta (n = 190) | Omicron (n = 223) | LRTI (n = 2380) |
|---|---|---|---|---|---|---|
Baseline characteristics | ||||||
Male sex | 1684 (70.6) | 1043 (73.4) | 367 (66.6) | 136 (71.6) | 138 (61.9) | 1506 (63.3) |
Age, years | 63.0 [54.0, 72.0] | 63.0 [54.0, 71.0] | 64.0 [54.0, 72.0] | 61.5 [49.2, 71.0] | 68.0 [54.0, 76.5] | 67.0 [56.0, 75.0] |
18–44 | 267 (11.2) | 133 (9.4) | 68 (12.3) | 31 (16.3) | 35 (15.7) | 300 (12.6) |
45–64 | 1030 (43.2) | 650 (45.7) | 230 (41.7) | 86 (45.3) | 64 (28.7) | 734 (30.8) |
65 or older | 1088 (45.6) | 638 (44.9) | 253 (45.9) | 73 (38.4) | 124 (55.6) | 1346 (56.6) |
Region of birth | ||||||
Africa | 171 (7.2) | 114 (8.0) | 31 (5.6) | 16 (8.4) | 10 (4.5) | 71 (3.0) |
The Americas | 124 (5.2) | 85 (6.0) | 27 (4.9) | 7 (3.7) | 5 (2.2) | 27 (1.1) |
Asia or Oceania | 547 (22.9) | 366 (25.8) | 100 (18.1) | 53 (27.9) | 28 (12.6) | 178 (7.5) |
Europe | 368 (15.4) | 210 (14.8) | 87 (15.8) | 39 (20.5) | 32 (14.3) | 302 (12.7) |
Sweden | 1172 (49.1) | 646 (45.5) | 305 (55.4) | 75 (39.5) | 146 (65.5) | 1801 (75.7) |
Missing | 3 (0.1) | 0 (0.0) | 1 (0.2) | 0 (0.0) | 2 (0.9) | 1 (0.0) |
Yearly disposable income quartile | ||||||
Quartile 1 | 920 (38.6) | 520 (36.6) | 201 (36.5) | 94 (49.5) | 105 (47.1) | 1007 (42.3) |
Quartile 2 | 626 (26.2) | 380 (26.7) | 145 (26.3) | 48 (25.3) | 53 (23.8) | 588 (24.7) |
Quartile 3 | 479 (20.1) | 298 (21.0) | 111 (20.1) | 29 (15.3) | 41 (18.4) | 423 (17.8) |
Quartile 4 | 353 (14.8) | 223 (15.7) | 93 (16.9) | 17 (8.9) | 20 (9.0) | 360 (15.1) |
Missing | 7 (0.3) | 0 (0.0) | 1 (0.2) | 2 (1.1) | 4 (1.8) | 2 (0.1) |
Cancer | 127 (5.3) | 72 (5.1) | 27 (4.9) | 8 (4.2) | 20 (9.0) | 327 (13.7) |
Cardiac or cerebrovascular disease | 503 (21.1) | 275 (19.4) | 115 (20.9) | 35 (18.4) | 78 (35.0) | 770 (32.4) |
Chronic kidney failure | 174 (7.3) | 86 (6.1) | 36 (6.5) | 16 (8.4) | 36 (16.1) | 212 (8.9) |
Chronic liver disease | 67 (2.8) | 39 (2.7) | 16 (2.9) | 3 (1.6) | 9 (4.0) | 160 (6.7) |
Chronic lung disease | 182 (7.6) | 100 (7.0) | 44 (8.0) | 12 (6.3) | 26 (11.7) | 451 (18.9) |
Diabetes (type 1 or 2) | 626 (26.2) | 380 (26.7) | 135 (24.5) | 50 (26.3) | 61 (27.4) | 540 (22.7) |
Hypertension | 1057 (44.3) | 638 (44.9) | 240 (43.6) | 73 (38.4) | 106 (47.5) | 1115 (46.8) |
Immunocompromised state | 288 (12.1) | 153 (10.8) | 61 (11.1) | 27 (14.2) | 47 (21.1) | 437 (18.4) |
Mental health disorder | 71 (3.0) | 36 (2.5) | 16 (2.9) | 4 (2.1) | 15 (6.7) | 138 (5.8) |
Neurological disease | 60 (2.5) | 34 (2.4) | 7 (1.3) | 4 (2.1) | 15 (6.7) | 176 (7.4) |
Obesity | 362 (15.2) | 187 (13.2) | 120 (21.8) | 27 (14.2) | 28 (12.6) | 183 (7.7) |
Charlson comorbidity index score | 0.0 [0.0, 2.0] | 0.0 [0.0, 2.0] | 0.0 [0.0, 2.0] | 0.0 [0.0, 1.0] | 1.0 [0.0, 3.0] | 1.0 [0.0, 3.0] |
0 | 1265 (53.0) | 761 (53.6) | 293 (53.2) | 120 (63.2) | 91 (40.8) | 868 (36.5) |
1–2 | 732 (30.7) | 450 (31.7) | 172 (31.2) | 43 (22.6) | 67 (30.0) | 708 (29.7) |
3–4 | 227 (9.5) | 124 (8.7) | 48 (8.7) | 17 (8.9) | 38 (17.0) | 432 (18.2) |
≥ 5 | 161 (6.8) | 86 (6.1) | 38 (6.9) | 10 (5.3) | 27 (12.1) | 372 (15.6) |
COVID-19 vaccination status before hospitalization | ||||||
Unvaccinated | 2158 (90.5) | 1421 (100.0) | 527 (95.6) | 140 (73.7) | 70 (31.4) | NA |
One dose | 31 (1.3) | 0 (0.0) | 20 (3.6) | 5 (2.6) | 6 (2.7) | NA |
Two doses | 106 (4.4) | 0 (0.0) | 4 (0.7) | 41 (21.6) | 61 (27.4) | NA |
Three doses | 67 (2.8) | 0 (0.0) | 0 (0.0) | 4 (2.1) | 63 (28.3) | NA |
Four doses | 23 (1.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 23 (10.3) | NA |
ICU characteristics | ||||||
Time to ICU admission from COVID-19 symptom onset | 10.0 [7.0, 13.0] | 10.0 [7.0, 13.0] | 10.0 [7.0, 13.0] | 10.0 [7.0, 14.0] | 3.0 [0.0, 8.0] | NA |
Missing | 49 (2.1) | 18 (1.3) | 16 (2.9) | 2 (1.1) | 13 (5.8) | NA |
SAPS 3 score | 56.0 [49.0, 65.0] | 56.0 [48.0, 63.0] | 57.0 [51.0, 66.0] | 56.0 [49.2, 66.0] | 59.0 [51.0, 70.5] | 63.0 [54.0, 73.0] |
PaO2/FiO2 ratio | 11.4 [8.9, 15.6] | 11.4 [9.0, 15.3] | 10.6 [8.5, 13.8] | 11.2 [8.6, 15.0] | 18.2 [11.2, 38.0] | 19.3 [12.1, 30.3] |
Missing | 292 (12.2) | 179 (12.6) | 50 (9.1) | 17 (8.9) | 46 (20.6) | 498 (20.9) |
Mechanical ventilation | 1379 (57.8) | 878 (61.8) | 287 (52.1) | 105 (55.3) | 109 (48.9) | 1307 (54.9) |
Duration | 10.9 [5.0, 21.2] | 11.9 [6.1, 22.3] | 11.2 [5.1, 22.5] | 9.3 [4.8, 14.8] | 3.6 [0.7, 9.5] | 7.2 [3.0, 15.3] |
NIV or HFNO | 1616 (67.8) | 903 (63.5) | 451 (81.9) | 155 (81.6) | 107 (48.0) | 1332 (56.0) |
Prone positioning | 989 (41.5) | 651 (45.8) | 225 (40.8) | 85 (44.7) | 28 (12.6) | 104 (4.4) |
Length of stay in ICU | 7.9 [2.9, 17.2] | 9.0 [3.7, 19.0] | 6.6 [2.9, 16.5] | 8.1 [3.2, 16.3] | 2.7 [0.9, 7.5] | 4.7 [1.7, 12.8] |
Length of stay in hospital | 21.0 [12.0, 39.0] | 22.0 [13.0, 41.0] | 21.0 [12.0, 40.0] | 19.0 [13.0, 32.0] | 14.0 [7.0, 29.0] | 19.0 [9.0, 39.0] |
Missing | 3 (0.1) | 1 (0.1) | 0 (0.0) | 0 (0.0) | 2 (0.9) | 7 (0.3) |