Factors affecting the risk of unscheduled ED visit within 96 hours after a non-transport decision by ambulance personnel
| Variable | Unscheduled visits | No unscheduled visits | OR (95% CI) for all non-transported and unintended* patients) | P value‡ |
| Age (years), median (IQR) | 2.98 (1.04–7.92) | 4.18 (1.47–10.62) | 0.96 (0.94 to 0.99) | 0.001 |
| Time of day† (hours), median (IQR) | 12.53 (8.07–16.62) | 9.83 (5.69–13.74) | 1.07 (1.05 to 1.10) | <0.001 |
| Shift | <0.001 | |||
| Day (09:00–21:00) | 118 (46.6%) | 1675 (65%) | 1 (reference) | |
| Night (21:00–09:00) | 135 (53.4%) | 901 (35%) | 2.13 (1.64 to 2.76) | |
| Symptom code ‘dyspnoea’ | <0.001 | |||
| No | 197 (77.9%) | 2213 (85.9%) | 1 (reference) | |
| Yes | 56 (22.1%) | 363 (14.1%) | 1.73 (1.25 to 2.36) | |
| Symptom code ‘low-energy fall’ | <0.001 | |||
| No | 229 (90.5%) | 2069 (80.3%) | 1 (reference) | |
| Yes | 24 (9.5%) | 507 (19.7%) | 0.43 (0.27 to 0.64) | |
| Symptom code ‘allergic reaction’ | 0.044 | |||
| No | 248 (98.0%) | 2447 (95.0%) | 1 (reference) | |
| Yes | 5 (2.0%) | 129 (5.0%) | 0.38 (0.13 to 0.85) | |
| Symptom code ‘vomiting/diarrhoea’ | 0.03 | |||
| No | 240 (94.9%) | 2510 (97.4%) | 1 (reference) | |
| Yes | 13 (5.1%) | 66 (2.6%) | 2.06 (1.07 to 3.67) | |
| Symptom code ‘mental illness’ | 0.019 | |||
| No | 242 (95.7%) | 2527 (98.1%) | 1 (reference) | |
| Yes | 11 (4.3%) | 49 (1.9%) | 2.34 (1.14 to 4.40) |
*Patients advised by ambulance personnel to visit the ED by transport other than ambulance were excluded from the analysis.
†Hours starting from 09:00=0 due to the shift schedule.
‡Mann-Whitney U test was used for continuous parameters and χ2 test was used for categorical parameters.
ED, emergency department.