Table 3. Discriminatory Performance of OSTA and the Candidate Models to Identify Men with Osteoporosis and Low BMD.
| Sensitivity | Specificity | PPV | NPV | NMC | NUDT | LR (+) | LR (-) | ROC | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| % (95% CI) | % (95% CI) | % (95% CI) | % (95% CI) | (95% CI) | (95% CI) | AUC (SE) | Statistical difference | |||||
| Osteoporosis (TFN≤-2.5 or TLS≤-2.5) | ||||||||||||
| Development dataset | ||||||||||||
| OSTA (≤0) | 86.2 (78.3, 92.1) | 49.7 (46.9, 52.6) | 13.2 (10.8, 15.9) | 97.6 (96.1, 98.7) | 138 | 503 | 1.72 (1.56, 1.88) | 0.28 (0.17, 0.44) | 0.680 (0.018) | |||
| OSTA (≤1) | 90.8 (83.8, 95.5) | 36.9 (34.2, 39.7) | 11.3 (9.3, 13.6) | 97.8 (96.1, 99.0) | 92 | 632 | 1.44 (1.34, 1.55) | 0.25 (0.14, 0.45) | 0.639 (0.016) | (ref) | ||
| Model 1 (≤-9) | 90.8 (83.8, 95.5) | 42.4 (39.6, 45.2) | 12.3 (10.1, 14.7) | 98.1 (96.6, 99.1) | 92 | 576 | 1.58 (1.46, 1.70) | 0.22 (0.12, 0.39) | 0.666 (0.016) | <0.001 | (ref) | |
| Model 2 (≤-10) | 91.7 (84.9, 96.2) | 41.2 (38.4, 44.0) | 12.1 (10.0, 14.6) | 98.3 (96.7, 99.2) | 83 | 589 | 1.56 (1.45, 1.68) | 0.20 (0.11, 0.38) | 0.665 (0.015) | 0.004 | 0.780 | (ref) |
| Model 3 (≤-12) | 90.8 (83.8, 95.5) | 43.3 (40.5, 46.1) | 12.4 (10.2, 14.9) | 98.2 (96.6, 99.1) | 92 | 567 | 1.60 (1.48, 1.73) | 0.21 (0.12, 0.38) | 0.671 (0.016) | <0.001 | 0.559 | 0.311 |
| Validation dataset | ||||||||||||
| OSTA (≤0) | 84.6 (75.5, 91.3) | 48.4 (45.3, 51.5) | 12.8 (10.2, 15.7) | 97.2 (95.4, 98.5) | 154 | 517 | 1.64 (1.47, 1.82) | 0.32 (0.20, 0.52) | 0.665 (0.021) | (ref) | ||
| OSTA (≤1) | 92.3 (84.8, 96.9) | 33.2 (30.3, 36.2) | 11.0 (8.9, 13.4) | 98.0 (95.9, 99.2) | 77 | 669 | 1.38 (1.28, 1.49) | 0.23 (0.11, 0.48) | 0.627 (0.016) | (ref) | ||
| Model 1 (≤-9) | 87.9 (79.4, 93.8) | 39.7 (36.7, 42.8) | 11.5 (9.3, 14.1) | 97.4 (95.3, 98.7) | 121 | 603 | 1.46 (1.33, 1.60) | 0.30 (0.17, 0.53) | 0.638 (0.019) | 0.365 | (ref) | |
| Model 2 (≤-10) | 85.7 (76.8, 92.2) | 37.9 (34.9, 40.9) | 11.0 (8.8, 13.5) | 96.7 (94.5, 98.3) | 143 | 622 | 1.38 (1.25, 1.52) | 0.38 (0.23, 0.63) | 0.618 (0.020) | 0.506 | 0.017 | (ref) |
| Model 3 (≤-12) | 89.0 (80.7, 94.6) | 39.5 (36.4, 42.5) | 11.6 (9.3, 14.2) | 97.6 (95.6, 98.8) | 110 | 606 | 1.47 (1.35, 1.60) | 0.28 (0.15, 0.50) | 0.642 (0.018) | 0.272 | 0.703 | 0.017 |
| Low BMD (TFN≤-2.0 or TLS≤-2.0) | ||||||||||||
| Development dataset | ||||||||||||
| OSTA (≤0) | 80.0 (74.6, 84.7) | 53.1 (50.1, 56.1) | 28.6 (25.3, 32.1) | 91.9 (89.4, 93.9) | 200 | 470 | 1.71 (1.56, 1.86) | 0.38 (0.29, 0.48) | 0.665 (0.015) | (ref) | ||
| OSTA (≤1) | 88.2 (83.6, 91.9) | 40.0 (37.1, 43.0) | 25.7 (22.8, 28.7) | 93.5 (90.9, 95.6) | 118 | 600 | 1.47 (1.38, 1.57) | 0.29 (0.21, 0.41) | 0.642 (0.013) | (ref) | ||
| Model 1 (≤-9) | 85.5 (80.6, 89.6) | 45.6 (42.6, 48.6) | 27.0 (24.0, 30.2) | 93.1 (90.5, 95.1) | 146 | 544 | 1.57 (1.46, 1.69) | 0.32 (0.23, 0.43) | 0.656 (0.013) | 0.091 | (ref) | |
| Model 2 (≤-10) | 85.5 (80.6, 89.6) | 44.2 (41.2, 47.2) | 26.5 (23.5, 29.6) | 92.8 (90.3, 94.9) | 146 | 559 | 1.53 (1.42, 1.65) | 0.33 (0.24, 0.45) | 0.648 (0.013) | 0.434 | 0.142 | (ref) |
| Model 3 (≤-12) | 85.1 (80.1, 89.2) | 46.5 (43.5, 49.6) | 27.2 (24.2, 30.5) | 93.0 (90.5, 95.0) | 149 | 535 | 1.59 (1.48, 1.71) | 0.32 (0.24, 0.43) | 0.658 (0.014) | 0.071 | 0.749 | 0.160 |
| Validation dataset | ||||||||||||
| OSTA (≤0) | 77.1 (70.1, 82.6) | 51.0 (47.7, 54.3) | 26.9 (23.4, 30.1) | 90.5 (88.0, 92.9) | 229 | 490 | 1.57 (1.43, 1.74) | 0.45 (0.35, 0.58) | 0.641 (0.017) | (ref) | ||
| OSTA (≤1) | 86.7 (81.3, 91.0) | 35.2 (32.1, 38.4) | 23.8 (20.8, 27.0) | 91.9 (88.5, 94.5) | 134 | 648 | 1.34 (1.25, 1.44) | 0.38 (0.27, 0.54) | 0.609 (0.014) | (ref) | ||
| Model 1 (≤-9) | 84.8 (79.2, 89.3) | 42.7 (39.4, 46.0) | 25.7 (22.4, 29.1) | 92.3 (89.3, 94.7) | 153 | 574 | 1.48 (1.36, 1.60) | 0.36 (0.26, 0.50) | 0.637 (0.015) | 0.004 | (ref) | |
| Model 2 (≤-10) | 86.2 (80.8, 90.6) | 41.1 (37.9, 44.4) | 25.5 (22.3, 28.8) | 92.7 (89.7, 95.1) | 139 | 589 | 1.46 (1.36, 1.58) | 0.34 (0.24, 0.48) | 0.636 (0.015) | 0.009 | 0.931 | (ref) |
| Model 3 (≤-12) | 86.7 (81.3, 91.0) | 42.7 (39.4, 46.0) | 26.1 (22.9, 29.5) | 93.2 (90.3, 95.4) | 134 | 574 | 1.50 (1.39, 1.63) | 0.32 (0.23, 0.46) | 0.647 (0.014) | 0.001 | 0.287 | 0.218 |
OSTA, Osteoporosis Self-assessment Tool for Asians; BMD, bone mineral density; PPV, positive predictive value; NPV, negative predictive value; NMC, the number of missed cases which represents the number of undetected osteoporotic subjects (i.e., false negatives) per 1000 subjects; NUDT, the number of unnecessary DXA tests which represents the number of subjects referred for DXA testing (i.e., false positives) per 1000 subjects; ROC, receiver operation characteristics; AUC, area under the curve; SE, standard error; TFN, T-score at femoral neck; TLS, T-score at lumbar spine; DXA, dual-energy X-ray absorptiometry; ALP, alkaline phosphatase.
Model 1 included age and weight, model 2 added regular exercise, and model 3 added low vitamin D and an elevated ALP.