Baseline characteristics of study population
| Baseline features | Derivation | Validation | ||||
| <70 years, n=8728 | ≥70 years, n=2079 | p Value | <70 years, n=8411 | ≥70 years, n=2069 | p Value | |
| Age, median, IQR | 44.8 (28.8–57.4) | 78.1 (73.9–83.6) | 44.8 (28.4–58.0) | 77.9 (73.9–83.0) | ||
| Male, n (%) | 4762 (54.6) | 995 (47.9) | <0.001 | 4597 (54.7) | 1044 (50.5) | 0.001 |
| Triage category, n (%) | <0.001 | <0.001 | ||||
| <10 min | 1921 (22.0) | 657 (31.6) | 1893 (22.5) | 683 (33.0) | ||
| <1 hour | 3567 (40.9) | 943 (45.4) | 3557 (42.3) | 966 (46.7) | ||
| <2 hours | 3205 (36.7) | 472 (22.7) | 2921 (34.7) | 410 (19.8) | ||
| <4 hours | 35 (0.4) | 7 (0.3) | 40 (0.5) | 10 (0.5) | ||
| Arrival mode, n (%) | <0.001 | <0.001 | ||||
| Self-referral | 4258 (48.8) | 467 (22.5) | 3794 (45.1) | 404 (19.5) | ||
| Ambulance/other institution | 1316 (15.1) | 596 (28.7) | 1659 (19.7) | 833 (40.3) | ||
| Referred by general practitioner/specialist | 3154 (36.1) | 1016 (48.9) | 2958 (35.2) | 832 (40.2) | ||
| Type of specialist | <0.001 | <0.001 | ||||
| Medicine | 3809 (43.6) | 1251 (60.2) | 3732 (44.4) | 1245 (60.2) | ||
| Surgery | 4919 (56.4) | 828 (39.8) | 4679 (55.6) | 824 (39.8) | ||
| Revisit to the ED, n (%) | 0.082 | 0.071 | ||||
| Visit <30 days | 922 (10.6) | 247 (11.9) | 873 (10.4) | 243 (11.7) | ||
| Chief complaint1 | <0.001 | <0.001 | ||||
| Minor trauma | 3656 (42.2) | 621 (30.1) | 3301 (39.6) | 641 (31.2) | ||
| Major trauma | 183 (2.1) | 32 (1.5) | 208 (2.5) | 28 (1.4) | ||
| Chest pain | 980 (11.3) | 302 (14.6) | 992 (11.9) | 329 (16.0) | ||
| Dyspnoea | 426 (4.9) | 221 (10.7) | 394 (4.7) | 179 (8.7) | ||
| Syncope | 219 (2.5) | 118 (5.7) | 241 (2.9) | 100 (4.9) | ||
| Psychiatric complaints | 219 (2.5) | 34 (1.6) | 230 (2.8) | 26 (1.3) | ||
| Malaise | 1032 (11.9) | 377 (18.3) | 1034 (12.4) | 403 (19.6) | ||
| Abdominal pain | 935 (10.7) | 183 (8.9) | 922 (11.1) | 183 (8.9) | ||
| Other | 1018 (11.7) | 177 (8.6) | 1019 (12.2) | 164 (8.0) | ||
| Vital signs | ||||||
| Systolic BP, mm Hg2 | 136 (21.4) | 145 (27.3) | <0.001 | 135 (21.5) | 145 (28.1) | <0.001 |
| O2 saturation, %3 median, IQR | 98 (98–100) | 98 (96–100) | <0.001 | 99 (97–100) | 98 (96–99) | <0.001 |
| Temperature, °C4 | 37.0 (0.8) | 36.9 (1.0) | <0.001 | 37.0 (0.8) | 36.9 (0.9) | <0.001 |
| Respiratory rate, per minute5 | 17.6 (4.6) | 18.7 (5.5) | 0.007 | 17.6 (4.8) | 18.6 (5.4) | <0.001 |
| Heart rate, per minute6 | 86 (20) | 84 (20) | <0.001 | 86 (21) | 84 (21) | <0.001 |
| Testing, n (%) | <0.001 | <0.001 | ||||
| Phlebotomised blood sample | 4714 (54.0) | 1606 (77.2) | 4583 (54.5) | 1599 (77.3) | ||
-Values are mean, SD unless noted otherwise.
-Vital parameters measured are O2, oxygen saturation, measured in percentage oxygenated haemoglobin; systolic BP, measured in millimetres of mercury; temperature, measured in °C; Heart rate and Respiratory rate, measured as times per minute.
-Number of measured values per age group: <70 years: 1: n=17 009; 2: n=9924; 3: n=10 018; 4: n=9953; 5: n=5807; 6: n=10 371. ≥70 years: 1: n=4118; 2: n=3232; 3: n=3208; 4: n=2890; 5: n=2302; 6: n=3292.
-p Values are measured by t-test for scale values and χ2 for categorical values, and Mann-Whitney U test for non-parametric variables.