Table 2. Baseline characteristics of model development cohort.
| Characteristics | Overall cohort | Derivation cohort | Validation cohort |
|---|---|---|---|
| n = 25,472 | n = 17,830 | n = 7,642 | |
| Age (y), mean (SD) | 63.2 (18.4) | 63.4 (18.4) | 62.8 (18.4) |
| Race, n (%) | |||
| Chinese | 15,940 (62.6) | 11,180 (62.7) | 4,760 (62.2) |
| Indian | 2,767 (10.9) | 1,937 (10.9) | 830 (10.9) |
| Malay | 4,178 (16.4) | 2,882 (16.2) | 1,296 (17.0) |
| Other | 2,587 (10.1) | 1,831 (10.2) | 756 (9.9) |
| Gender (male), n (%) | 13,638 (53.5) | 9,513 (53.4) | 4,125 (54.0) |
| Staying at rental flat, n (%) | 1,308 (5.1) | 922 (5.2) | 386 (5.1) |
| Healthcare utilization history, mean (SD) | |||
| Hospital admission previous 1 y | 0.98 (2.1) | 0.98 (2.1) | 0.97 (2.1) |
| Emergency attendance previous half year | 0.24 (1.4) | 0.25 (1.4) | 0.24 (1.4) |
| Medical social referral previous 1 y, n (%) | 5,011 (19.7) | 3,554 (19.9) | 1,457 (19.1) |
| Subspecialty, n (%) | |||
| Acute medicine | 6,198 (24.3) | 4,320 (24.2) | 1,878 (24.6) |
| Endocrinology | 1,180 (4.6) | 817 (4.6) | 363 (4.7) |
| Gastroenterology and hepatology | 1,508 (5.9) | 1,065 (6.0) | 443 (5.8) |
| General cardiology | 2,899 (11.4) | 1,998 (11.2) | 901 (11.8) |
| General medicine | 4,419 (17.4) | 3,107 (17.4) | 1,312 (17.2) |
| Geriatric medicine | 1,136 (4.5) | 828 (4.6) | 308 (4.0) |
| Hematology | 1 (0.0) | 1 (0.0) | 0 (0.0) |
| Infectious diseases | 1,829 (7.2) | 1,310 (7.4) | 519 (6.8) |
| Medical oncology | 139 (0.5) | 97 (0.5) | 42 (0.5) |
| Neurology | 1,912 (7.5) | 1,322 (7.4) | 590 (7.7) |
| Rehabilitation medicine | 147 (0.6) | 103 (0.6) | 44 (0.6) |
| Renal medicine | 1,150 (4.5) | 816 (4.6) | 334 (4.4) |
| Respiratory medicine | 2,953 (11.6) | 2,045 (11.5) | 908 (11.9) |
| Rheumatology | 1 (0.0) | 1 (0.0) | 0 (0.0) |
| Functional components, n (%) | |||
| Dependent | 1,433 (8.0) | 632 (8.3) | 2,065 (8.1) |
| Needs assistance | 10,289 (57.7) | 4,406 (57.6) | 14,695(57.7) |
| Independent | 6,108 (34.3) | 2,604 (34.1) | 8,712 (34.2) |
| Emergency admission, n (%) | 24,821 (97.4) | 17,393 (97.6) | 7,428 (97.2) |
| Admission or transfer to ICU in previous half year, mean (%) | 951 (3.7) | 662 (3.7) | 289 (3.8) |
| Length of stay at index admission, mean (SD) | 4.4 (6.9) | 4.4 (6.3) | 4.5 (8.0) |
| Total length of stay of previous 1-year admissions, n (%) | |||
| 0 d | 15,637 (61.4) | 10,946 (61.4) | 4,691 (61.4) |
| 1–10 d | 6,180 (24.3) | 4,301 (24.1) | 1,879 (24.6) |
| 11–20 d | 1,847 (7.2) | 1,298 (7.3) | 549 (7.2) |
| 21–30 d | 805 (3.2) | 574 (3.2) | 231 (3.0) |
| 31–40 d | 419 (1.6) | 292 (1.6) | 127 (1.7) |
| 41–50 d | 233 (0.9) | 169 (1.0) | 64 (0.8) |
| 51 d and above | 351 (1.4) | 250 (1.4) | 101 (1.3) |
| Charlson Comorbidity Index, n (%) | |||
| 0 | 10,022 (39.4) | 7,036 (39.5) | 2,986 (39.1) |
| 1 | 3,308 (13.0) | 2,266 (12.7) | 1,042 (13.6) |
| 2+ | 12,142 (47.6) | 8,528 (47.8) | 3,614 (47.3) |
| Preadmission chronic medication, n (%) | |||
| 0 | 5,758 (22.6) | 4,043 (22.7) | 1,715 (22.4) |
| 1–5 | 9,310 (36.6) | 6,524 (36.6) | 2,786 (36.5) |
| 6+ | 10,404 (40.8) | 7,263 (40.7) | 3,141 (41.1) |
| Index discharge class, n (%) | |||
| Class A | 2,276 (8.9) | 1,585 (8.9) | 691 (9.0) |
| Class B1 | 1,098 (4.3) | 765 (4.3) | 333 (4.4) |
| Class B2 | 6,118 (24.0) | 4,330 (24.3) | 1,788 (23.4) |
| Class C | 15,980 (62.8) | 11,150 (62.5) | 4,830 (63.2) |
Abbreviations: ICU, intensive care unit; SD, standard deviation.