Table 3.
Diagnostic accuracy of biomarkers and radius high-resolution peripheral quantitative computed tomography for identifying patients with low bone turnover
| Variables | AUC (95% CI) | Criterion | Sensitivity, % | Specificity, % | PPV, % | NPV, % |
|---|---|---|---|---|---|---|
| Biomarkers | ||||||
| iPTH | 0.563 (0.40 to 0.72) | ≤183 pg/ml | 70 | 53 | 32 | 85 |
| Intact PINP | 0.794 (0.64 to 0.90) | ≤57 ng/ml | 80 | 75 | 50 | 92 |
| Total PINP | 0.719 (0.56 to 0.85) | ≤124 ng/ml | 80 | 68 | 44 | 91 |
| bALP | 0.824 (0.67 to 0.93) | ≤21 μg/L | 89 | 77 | 53 | 96 |
| tALP | 0.753 (0.60 to 0.87) | ≤88 IU/L | 91 | 63 | 46 | 95 |
| CTX | 0.766 (0.61 to 0.88) | ≤0.84 ng/ml | 60 | 84 | 55 | 87 |
| TRAP5b | 0.799 (0.64 to 0.91) | ≤4.6 U/L | 89 | 71 | 47 | 96 |
| Radius HR-pQCT Z score | ||||||
| Total vBMD | 0.811 (0.65 to 0.92) | >−1.0 | 100 | 59 | 45 | 100 |
| Cortical BV/TV | 0.802 (0.64 to 0.92) | >−0.2 | 89 | 63 | 44 | 94 |
| Combined variables | ||||||
| bALP and radius total vBMD Z score | 0.797 (0.62 to 0.92) | Not available | 100 | 58 | 39 | 100 |
AUC, area under the receiver operating characteristic curve; 95% CI, 95% confidence interval; PPV, positive predictive value; NPV, negative predictive value; iPTH, intact parathyroid hormone; PINP, procollagen type 1 N-terminal propeptide; bALP, bone alkaline phosphatase; tALP, total alkaline phosphatase; CTX, collagen type 1 crosslinked C-telopeptide; TRAP5b, tartrate-resistant acid phosphatase 5b; HR-pQCT, high-resolution peripheral quantitative computed tomography; vBMD, volumetric bone mineral density; BV/TV, bone volume/tissue volume.