Effect on mortality of increasing time from patient arrival to inpatient bed transfer as shown by the standardised mortality ratio and number needed to harm
| Hours in the ED | SMR | Percentage change in the SMR | 95% lower confidence limit for the SMR | 95% upper confidence limit for the SMR | Adjusted absolute mortality rate | Number needed to harm (30-day mortality) |
| Up to 4 hours | 0.94 | −6% | 0.92 | 0.95 | 8.2% | −191 |
| 4–6 hours | 1.06 | 6% | 1.04 | 1.08 | 9.2% | 191 |
| 6–8 hours | 1.14 | 14% | 1.11 | 1.18 | 9.9% | 82 |
| 8–12 hours | 1.16 | 16% | 1.12 | 1.21 | 10.1% | 72 |
ED, emergency department; vW, summary score developed by van Walraven.18