Standardised age-adjusted mortality ratios for the 1995–7 and 2004–5 cohorts
| Study cohort | No of patients | Deaths by 180 days | Survival at 180 days (95% CI) | Expected deaths by 180 days | Expected survival at 180 days (%) | SMR (95% CI) |
| 1995–7 | 552 | 141 | 74.5% (70.6% to 77.9%) | 11.55 | 97.9 | 12.2 (10.3 to 14.4) |
| 2004–5 | 396 | 56 | 85.7% (81.8% to 88.8%) | 11.69 | 97.0 | 4.8 (3.6 to 6.2) |
SMR, standardised mortality ratio.