Characteristics of admissions with or without adverse events and/or incidents
| Variable n (column %) | Cohort | Neither AEs/I | Only I | Only AEs | Both AEs/I | P values |
| 26 383 (100.0) | 20 676 (78.4) | 869 (3.3) | 4108 (15.6) | 730 (2.8) | ||
| Complaint filed | 33 (0.1) | 20 (0.1) | 0 (0) | 9 (0.2) | 4 (0.5) | 0.006 |
| No. of incidents | – | – | ||||
| Total | 2162 | 1024 | 1138 | <0.001 | ||
| Median | 0 | 1 | 1 | |||
| Mean | 0.1±0.4 | 1.2±0.5 | 1.6±1.1 | |||
| No. of AEs | <0.001 | |||||
| Total | 8870 | – | – | 6897 | 1973 | |
| Median | 0 | 1 | 2 | |||
| Mean | 0.3±1.0 | 1.7±1.6 | 2.7±2.5 | |||
| Maximum AE severity* | ||||||
| No AEs | 21 545 (81.7) | – | – | 2901 (70.6) | 452 (61.9) | <0.001 |
| 1 | 3353 (12.7) | 665 (16.2) | 164 (22.5) | |||
| 2 | 829 (3.1) | 192 (4.7) | 63 (8.6) | |||
| 3 | 225 (1.0) | 287 (7.0) | 35 (4.8) | |||
| 4 | 322 (1.2) | 63 (1.5) | 16 (2.2) | |||
| Undetermined | 79 (0.3) | |||||
| Serious AEs (severity≥2) | 1406 (5.3) | 1144 (27.8) | 262 (35.9) | <0.001 | ||
| AE cascades (≥3 AEs) | 845 (3.2) | – | – | 581 (14.1) | 264 (36.2) | <0.001 |
| Male gender | 14 009 (53.1) | 10 765 (52.1) | 490 (56.4) | 2298 (55.9) | 456 (62.5) | <0.001 |
| Age (years) | 52.6±21.0 | 50.7±21.4 | 58.5±16.2 | 59.6±18.3 | 61.1±15.3 | <0.001 |
| Received surgery | 19 154 (72.6) | 14 288 (69.1) | 664 (76.4) | 3525 (85.8) | 677 (92.7) | <0.001 |
| ASA at first surgery† | ||||||
| I | 4620 (24.1) | 4198 (29.4) | 72 (10.8) | 335 (9.5) | 15 (2.2) | <0.001 |
| II | 6619 (34.6) | 4968 (34.8) | 240 (36.1) | 1242 (35.2) | 169 (25.0) | |
| III | 2428 (12.7) | 1346 (9.4) | 136 (20.5) | 772 (21.9) | 174 (25.7) | |
| IV | 225 (1.2) | 79 (0.6) | 7 (1.1) | 121 (3.4) | 18 (2.7) | |
| V | 31 (0.2) | 8 (0.1) | 1 (0.2) | 18 (0.5) | 4 (0.6) | |
| Missing | 5231 (27.3) | 3689 (25.8) | 208 (31.3) | 1037 (19.4) | 297 (43.9) | |
| Status at first surgery† | <0.001 | |||||
| Elective | 11 284 (58.9) | 8837 (61.8) | 383 (57.7) | 1804 (51.2) | 260 (38.4) | |
| Emergency | 2639 (13.8) | 1762 (12.3) | 73 (11.0) | 684 (19.4) | 120 (17.7) | |
| Missing | 5231 (27.3) | 3689 (25.8) | 208 (31.3) | 1037 (29.4) | 297 (43.9) | |
| Length of stay (days) | <0.001 | |||||
| Mean | 6.83±12.0 | 4.50±7.5 | 7.76±7.9 | 14.49±17.6 | 28.7±29.1 | |
| Median | 3.0 | 2.0 | 6.0 | 10.0 | 19.0 | |
| Followed by readmission‡ | 2666 (10.1) | 1643 (7.9) | 97 (11.2) | 791 (19.3) | 135 (18.5) | <0.001 |
*Severity levels: (1) recovery without (re)operation; (2) recovery with (re)operation; (3) (potential) irreversible harm; (4) death.
†ASA and emergent (rather than elective) status at the first surgical procedure during admission, thus only available for cases who received surgery and presented as % of patients who received surgery (ie, total n=19,154).
‡Whether a readmission followed within 30 days after discharge.
AE, adverse event; I, patient safety incident; No, number; ASA, American Society of Anesthesiologists.