Univariate analysis for mortality and postoperative SARS-CoV-2 infection, with the variables selected in the exploratory factorial analysis
| Mortality | Postoperative SARS-CoV-2 infection | |||||
| Alive (30 days) | Dead (30 days) | P value | Not infected (30 days) | Infected (30 days) | P value | |
| Age | 54 | 63.5 | <0.001 | 54.5 | 58.1 | 0.393 |
| ASA grade | <0.001 | 0.261 | ||||
| 1, n (%) | 376 (96.4) | 14 (3.6) | 389 (99.5) | 2 (0.5) | ||
| 2, n (%) | 571 (96.1) | 23 (3.9) | 584 (98.3) | 10 (1.7) | ||
| 3, n (%) | 482 (91.8) | 43 (8.2) | 515 (98.1) | 10 (1.9) | ||
| 4, n (%) | 98 (85.2) | 17 (14.8) | 113 (98.3) | 2 (1.7) | ||
| 5, n (%) | 7 (53.8) | 6 (46.2) | 13 (100.0) | 0 (0.0) | ||
| Previous medical conditions | 0.033 | 0.039 | ||||
| At least one, n (%) | 1228 (93.0) | 93 (7) | 1282 (98.2) | 23 (1.8) | ||
| None, n (%) | 342 (96.1) | 14 (3.9) | 352 (99.7) | 1 (0.3) | ||
| High blood pressure | 0.002 | 0.082 | ||||
| No, n (%) | 1002 (95.1) | 52 (4.9) | 1043 (99.0) | 11 (1.0) | ||
| Yes, n (%) | 568 (91.2) | 55 (8.8) | 610 (97.9) | 13 (2.1) | ||
| Diabetes mellitus | 0.013 | 0.572 | ||||
| No, n (%) | 1319 (94.3) | 80 (5.7) | 1380 (98.6) | 19 (1.4) | ||
| Yes, n (%) | 251 (90.3) | 27 (9.7) | 273 (98.2) | 5 (1.8) | ||
| GCS 3–8 | <0.001 | 0.183 | ||||
| No, n (%) | 1492 (95.5) | 71 (4.5) | 1539 (98.5) | 24 (1.5) | ||
| Yes, n (%) | 78 (68.4) | 36 (33.6) | 114 (100) | 0 (0) | ||
| Preoperative neurological deficit, n (%) | ||||||
| None | 573 (97.0) | 18 (3.0) | <0.001 | 577 (98.5) | 9 (1.5) | 0.826 |
| Language | 137 (88.4) | 18 (11.6) | 0.005 | 145 (96) | 6 (4) | 0.006 |
| Motor | 391 (92.2) | 33 (7.8) | 0.172 | 408 (97.6) | 10 (2.4) | 0.062 |
| Cognitive impairment | 264 (91.0) | 26 (9.0) | 0.048 | 277 (97.2) | 8 (2.8) | 0.035 |
| No reliable (altered mental status) | 66 (67.6) | 32 (32.7) | <0.001 | 93 (100) | 0 (0) | 0.229 |
| Community COVID-19 incidence (cases/105 people/week) (median; IQR) | 8 (19) | 22 (67) | <0.001 | 8 (19) | 132 (216) | <0.001 |
| Screening swab test <72 hours preoperatively | 0.064 | <0.001 | ||||
| No, n (%) | 704 (92.5) | 57 (7.5) | 743 (97.1) | 23 (2.9) | ||
| Yes, n (%) | 861 (94.7) | 48 (5.3) | 908 (99.9) | 1 (0.1) | ||
| SARS-CoV-2 perioperative infection | <0.001 | |||||
| No, n (%) | 1540 (94.3) | 93 (5.7) | ||||
| Yes, n (%) | 30 (68.2) | 14 (31.8) | ||||
| Urgent surgery | <0.001 | 0.166 | ||||
| No, n (%) | 644 (98.8) | 8 (1.2) | 1163 (98.3) | 20 (1.7) | ||
| Yes, n (%) | 446 (87.5) | 64 (12.5) | 490 (99.2) | 4 (0.8) | ||
| General anaesthesia, n (%) | 1373 (93.4) | 97 (6.6) | 0.338 | 1447 (98.4) | 23 (1.6) | 0.222 |
| Preoperative airway support, n (%) | 90 (70.9) | 37 (29.1) | <0.001 | 124 (97.6) | 3 (2.4) | 0.359 |
| Postperative airway support, n (%) | 144 (74.6) | 49 (25.4) | <0.001 | 187 (96.9) | 6 (3.1) | 0.017 |
| Length of surgery (min) | 163.41 | 152.58 | 0.370 | 162.3 | 186.8 | 0.324 |
| Postoperative sepsis, n (%) | 38 (84.4) | 7 (15.6) | 0.011 | 39 (90.7) | 4 (9.3) | <0.001 |
| Postoperative neurological worsening, n (%) | 88 (72.7) | 33 (27.3) | <0.001 | 113 (96.6) | 4 (3.4) | 0.064 |
| Postoperative pneumonia, n (%) | 56 (74.7) | 19 (25.3) | <0.001 | 70 (93.3) | 5 (6.7) | <0.001 |
| Postoperative blood transfusion, n (%) | 28 (77.8) | 8 (22.2) | <0.001 | 30 (96.8) | 1 (3.2) | 0.403 |
| Suffering one or more complications, n (%) | 309 (83.1) | 63 (16.9) | <0.001 | 348 (96.1) | 14 (3.9) | <0.001 |
| Reoperation | 0.007 | 0.078 | ||||
| No, n (%) | 1371 (94.2) | 84 (5.8) | 1420 (98.7) | 18 (1.3) | ||
| Yes, n (%) | 195 (89.4) | 23 (10.6) | 209 (97.2) | 6 (2.8) | ||
| Resources shortage (surgeon opinion) | 0.664 | 0.256 | ||||
| No, n (%) | 1505 (93.7) | 102 (6.3) | 1585 (98.6) | 22 (1.4) | ||
| Yes, n (%) | 60 (92.3) | 5 (7.7) | 63 (96.9) | 2 (3.1) | ||
ASA, American Society of Anesthesiologists; GCS, Glasgow Coma Scale.