| Type of adverse event | Adverse events n (%) | Preventable adverse events n (%*) | Mean extra bed days per adverse event | SE of mean | Total extra bed days in the sample |
| Hospital acquired infection | 19 (14.0) | 2 (11) | 7.1 | 1.5 | 135 |
| Post-operative infection | 23 (16.9) | 3 (13) | 7.4 | 1.6 | 170 |
| Other operative complications | 27 (19.9) | 7 (26) | 3.5 | 0.8 | 94 |
| Diagnostic adverse event | 7 (5.1) | 4 (57) | 6.4 | 2.0 | 45 |
| Pressure ulcer | 12 (8.8) | 2 (17) | 7.3 | 1.6 | 87 |
| Drug complication | 19 (14.0) | 1 (5) | 5.1 | 1.2 | 96 |
| Fall | 3 (2.2) | 0 (0) | 12.3 | 6.7 | 37 |
| Procedural adverse event | 11 (8.1) | 6 (55) | 6.6 | 2.6 | 73 |
| Clinical management adverse event | 10 (7.4) | 4 (40) | 6.5 | 2.1 | 65 |
| Other types of adverse event | 5 (3.7) | 0 (0) | 13.2 | 7.4 | 66 |
| Total adverse events | 136 (100) | 29 (21) | 6.5 | 0.6 | 868 |
*Percentages are of the total number of adverse events reported in the previous column; the confidence score for assessing the preventability is ⩾4.