Table 1. Baseline Characteristics of the Study Cohorta.
| Characteristic | Training (n = 224 666) | Validation (n = 56 167) | Testing (n = 42 676) |
|---|---|---|---|
| Age, mean (SD), y | 63.60 (16.90) | 63.58 (16.87) | 64.85 (16.80) |
| Sex | |||
| Male | 111 240 (49.5) | 27 740 (49.4) | 21 120 (49.5) |
| Female | 113 426 (50.5) | 28 427 (50.6) | 21 556 (50.5) |
| Race/ethnicity | |||
| Chinese | 167 004 (74.3) | 41 765 (74.4) | 31 441 (73.7) |
| Indian | 22 403 (10.0) | 5592 (10.0) | 4440 (10.4) |
| Malay | 29 040 (12.9) | 7213 (12.8) | 5465 (12.8) |
| Other | 6219 (2.8) | 1597 (2.8) | 1330 (3.1) |
| PACS triage categories | |||
| P1 | 39 548 (17.6) | 9823 (17.5) | 9913 (23.2) |
| P2 | 128 644 (57.3) | 32 058 (57.1) | 22 885 (53.6) |
| P3 and P4 | 56 474 (25.1) | 14 286 (25.4) | 9878 (23.1) |
| Shift time | |||
| 8 am to 4 pm | 113 758 (50.6) | 28 461 (50.7) | 21 870 (51.2) |
| 4 pm to midnight | 84 503 (37.6) | 21 050 (37.5) | 15 907 (37.3) |
| Midnight to 8 am | 26 405 (11.8) | 6656 (11.9) | 4899 (11.5) |
| Day of week | |||
| Friday | 31 553 (14.0) | 7893 (14.1) | 5839 (13.7) |
| Monday | 37 703 (16.8) | 9581 (17.1) | 7139 (16.7) |
| Weekend | 57 785 (25.7) | 14 283 (25.4) | 10 901 (25.5) |
| Midweek | 97 625 (43.5) | 24 410 (43.5) | 18 797 (44.0) |
| Vital signs, mean (SD) | |||
| Pulse, /min | 81.57 (16.41) | 81.62 (16.37) | 85.95 (18.36) |
| Respiration, /min | 17.80 (1.57) | 17.80 (1.59) | 18.23 (2.04) |
| Spo2, % | 98.12 (2.84) | 98.12 (2.70) | 97.34 (4.18) |
| Blood pressure, mm Hg | |||
| Diastolic | 70.99 (13.23) | 71.01 (13.20) | 72.36 (13.95) |
| Systolic | 133.77 (24.49) | 133.80 (24.58) | 137.73 (27.87) |
| Comorbidities | |||
| Myocardial infarction | 14 927 (6.6) | 3801 (6.8) | 2841 (6.7) |
| Congestive heart failure | 28 511 (12.7) | 7136 (12.7) | 4897 (11.5) |
| Peripheral vascular disease | 14 531 (6.5) | 3539 (6.3) | 2541 (6.0) |
| Stroke | 32 993 (14.7) | 8062 (14.4) | 5062 (11.9) |
| Dementia | 6901 (3.1) | 1699 (3.0) | 1515 (3.6) |
| Chronic pulmonary disease | 24 275 (10.8) | 6138 (10.9) | 3912 (9.2) |
| Rheumatoid disease | 3341 (1.5) | 881 (1.6) | 615 (1.4) |
| Peptic ulcer disease | 9879 (4.4) | 2505 (4.5) | 1362 (3.2) |
| Diabetes | |||
| None | 145 889 (64.9) | 36 457 (64.9) | 27 204 (63.7) |
| Diabetes without chronic complications | 24 268 (10.8) | 6064 (10.8) | 1247 (2.9) |
| Diabetes with complications | 54 509 (24.3) | 13 646 (24.3) | 14 225 (33.3) |
| Hemiplegia or paraplegia | 14 545 (6.5) | 3609 (6.4) | 1880 (4.4) |
| Kidney disease | 49 884 (22.2) | 12 483 (22.2) | 10 377 (24.3) |
| Cancer | |||
| None | 185 121 (82.4) | 46 251 (82.3) | 35 374 (82.9) |
| Local tumor, leukemia, and lymphoma | 20 838 (9.3) | 5136 (9.1) | 3613 (8.5) |
| Metastatic solid tumor | 18 707 (8.3) | 4780 (8.5) | 3689 (8.6) |
| Liver disease | |||
| None | 209 865 (93.4) | 52 562 (93.6) | 39 704 (93.0) |
| Mild liver disease | 11 112 (4.9) | 2676 (4.8) | 2156 (5.1) |
| Severe liver disease | 3689 (1.6) | 929 (1.7) | 816 (1.9) |
| Health care use, mean (SD) | |||
| Emergency admissions in the past year | 1.05 (2.35) | 1.05 (2.35) | 1.12 (2.51) |
| Operations in the past year | 0.20 (0.72) | 0.20 (0.72) | 0.28 (0.94) |
| ICU admissions in the past year | 0.03 (0.26) | 0.02 (0.26) | 0.03 (0.29) |
| HD admissions in the past year | 0.10 (0.51) | 0.10 (0.51) | 0.08 (0.45) |
| Mortality-related outcomes | |||
| 2 d | 1801 (0.8) | 449 (0.8) | 295 (0.7) |
| 3 d | 2464 (1.1) | 622 (1.1) | 416 (1.0) |
| 7 d | 4888 (2.2) | 1241 (2.2) | 779 (1.8) |
| 14 d | 8040 (3.6) | 2009 (3.6) | 1349 (3.2) |
| Inpatient | 8616 (3.8) | 2151 (3.8) | 1515 (3.6) |
| 30 d | 13 244 (5.9) | 3285 (5.8) | 2310 (5.4) |
Abbreviations: HD, high-dependency; ICU, intensive care unit; PACS, Patient Acuity Category Scale; Spo2, oxygen saturation as measured by pulse oximetry.
a
Data are presented as number (percentage) of patients unless otherwise indicated.