Table 4.
Osteoporosis classification results at 95% PPV and 95% NPV thresholds on Hologic testing data.
| Threshold with high PPV ≥95% | ||
|---|---|---|
| Hip | Spine | |
| Threshold BMD (g/cm2), T-score (T1) | 0.513, −2.9 | −3.0* |
| PPV for osteoporosis | ||
| TP/(TP + FP), n/N | 524/549 | 4750/5030 |
| PPV (95% CI) | 95.5 (93.5–96.8) | 94.4 (93.8–95.0) |
| PPV for 10-year major fracture risk ≥20% | NA | |
| TP/(TP + FP), n/N | 230/283 | |
| PPV (%, 95% CI) | 81.3 (76.9–85.0) | |
| PPV for 10-year hip fracture risk ≥3% | NA | |
| TP/(TP + FP), n/N | 492/498 | |
| PPV (95% CI) | 98.8 (97.4–99.5) | |
| Threshold with high NPV ≥95% | ||
| Threshold BMD (g/cm2), T-score (T2) | 0.580, −2.3 | −2.1* |
| NPV for osteoporosis | ||
| TN/(TN + FN), n/N | 3812/4008 | 7418/7765 |
| NPV (95% CI) | 95.1 (94.5–95.6) | 95.5 (95.1–96.0) |
| NPV for 10-year major fracture risk ≥20% | NA | |
| TN/(TN + FN), n/N | 3884/3953 | |
| NPV (95% CI) | 98.3 (97.8–98.6) | |
| NPV for 10-year hip fracture risk ≥3% | NA | |
| TN/(TN + FN), n/N | 2575/2839 | |
| NPV (95% CI) | 90.7 (89.8–91.5) | |
| Prediction categorization | ||
| Patient number (%) | ||
| Predicted BMD or T-score <T1 | 549 (10.6) | 5030 (27.7) |
| T1 ≤ predicted BMD or T-score <T2 | 607 (11.8) | 5380 (29.6) |
| Predicted BMD or T-score ≥T2 | 4008 (77.6) | 7765 (42.7) |
FN false negative, FP false positive, NA not available, NPV negative predictive value, PPV positive predictive value, TN true negative, TP true positive.
*Based on the vertebrae with the lowest T-score.