Table 1.
The 22 patient characteristics used as an input vector for the binary classification and the clinical outcome of length of stay > 2 days. Values are count (%) unless otherwise specified
| Factor | No. of patients | Missing |
|---|---|---|
| Mean age [SD] | 68 [10] | 0 (0) |
| Mean BMI [SD] | 28 [5] | 100 (1) |
| Female sex | 6,213 (59) | 0 (0) |
| Walking aid | 2,391 (23) | 195 (2) |
| Living alone | 3,632 (34) | 80 (1) |
| In institution | 75 (1) | |
| Smoking | 1,347 (13) | 89 (1) |
| Alcohol > 24g/day | 790 (8) | 91 (1) |
| Total knee arthroplasty | 4,448 (42) | 0 (0) |
| Psychiatric disease | 1,520 (14) | 0 (0) |
| Cardiac disease | 1,439 (14) | 106 (1) |
| Pulmonary disease | 945 (9) | 64 (1) |
| Hypertension | 5,911 (56) | 0 (0) |
| Non-insulin-dependent diabetes mellitus | 925 (9) | 61 (1) |
| Insulin-dependent diabetes mellitus | 199 (2) | |
| Anticoagulants | 821 (28) | 0 (0) |
| Preoperative anemia | 2,552 (24) | 155 (2) |
| Hypercholesterolemia | 3,102 (29) | 76 (1) |
| Previous cerebral attack | 582 (6) | 158 (2) |
| Previous thromboembolism | 737 (7) | 140 (1) |
| Cancer | 328 (3) | 98 (1) |
| Kidney disease | 176 (2) | 244 (2) |
| LOS > 2 days | 1,863 (18) | 0 (0) |
Characteristics are expressed in a vector for each patient when performing the binary classification. Values are represented as a count of patients carrying each attribute unless specified otherwise.