| Expected mortality | Actual mortality | p | |
|---|---|---|---|
| Sheffield 0 | 15/39 (38.5%) | 0/5 (0.0%) | 0.14 |
| Sheffield 1 | 53/100 (53.0%) | 5/12 (41.7%) | 0.54 |
| Sheffield 2 | 68/94 (72.3%) | 16/22 (72.7%) | 1 |
| Sheffield 3 | 40/51 (78.4%) | 36/39 (92.3%) | 0.08 |
| Levine 0–1 | 110/799 (13.8%) | 14/29 (48.3%) | <0.001 |
| Levine 2 | 130/719 (18.1%) | 7/10 (70.0%) | <0.001 |
| Levine 3 | 180/563 (31.9%) | 26/29 (89.7%) | <0.001 |
| Levine 4+ | 299/647 (46.2%) | 10/10 (100%) | <0.001 |