Table 5. Comparison of performance for logistic regression and random forest of validation set in men aged over 50-year-old and postmenopausal women.
| Characteristics | Risk factors for osteopenia | Risk factors for osteoporosis | |||
|---|---|---|---|---|---|
| LG1† | RF1† | LG2¶ | RF2¶ | ||
| Lumbar spine | |||||
| Patients with osteopenia (N=179) | |||||
| No. of true positive/false negative | 133/3 | 131/5 | |||
| No. of true negative/false positive | 1/42 | 3/40 | |||
| Patients with osteoporosis (N=299) | |||||
| No. of true positive/false negative | 130/27 | 116/41 | |||
| No. of true negative/false positive | 28/114 | 55/87 | |||
| Sensitivity, % | 97.8 | 96.3 | 82.8 | 73.9 | |
| Specificity, % | 2.3 | 7.0 | 19.7 | 38.7 | |
| OOB error estimate, % | 29.2 | 42.5 | |||
| Test error estimate, % | 25.1 | 29.1 | 47.2 | 42.5 | |
| Femoral neck | |||||
| Patients with osteopenia (N=257) | |||||
| No. of true positive/false negative | 196/5 | 197/4 | |||
| No. of true negative/false positive | 5/51 | 4/52 | |||
| Patients with osteoporosis (N=285) | |||||
| No. of true positive/false negative | 14/69 | 19/64 | |||
| No. of true negative/false positive | 182/20 | 183/19 | |||
| Sensitivity, % | 97.5 | 98.0 | 16.9 | 22.9 | |
| Specificity, % | 8.9 | 7.1 | 90.1 | 90.6 | |
| OOB error estimate, % | 26.1 | 34.0 | |||
| Test error estimate, % | 21.8 | 21.8 | 31.2 | 29.1 | |
| Total hips | |||||
| Patients with osteopenia (N=295) | |||||
| No. of true positive/false negative | 156/40 | 147/49 | |||
| No. of true negative/false positive | 34/65 | 39/60 | |||
| Patients with osteoporosis (N=241) | |||||
| No. of true positive/false negative | 4/47 | 7/44 | |||
| No. of true negative/false positive | 182/8 | 179/11 | |||
| Sensitivity, % | 79.6 | 75.0 | 7.8 | 13.8 | |
| Specificity, % | 34.3 | 39.4 | 95.8 | 94.2 | |
| OOB error estimate, % | 34.9 | 22.4 | |||
| Test error estimate, % | 35.6 | 36.9 | 22.8 | 22.8 | |
†, to explore the risk for osteopenia to patients with normal bone mineral density; ¶, to explore the risk for osteoporosis to patients with osteopenia. RF, random forest; OOB, out-of-bag; LG, logistic regression.