TABLE 4.
Performance characteristics of the single biomarker for diagnosing LS 1-4 BMD change
| Variable | AUC (95% CI) | P | Cut-off value | Sensitivity (%, 95% CI) | Specificity (%, 95% CI) | PPV (%, 95% CI) | NPV (%, 95% CI) | Kappa value (95% CI) | DE (%, 95% CI) |
| 1 y N-MID (ng/mL) | 0.751 (0.669-0.821) | < 0.001 | 13.24 | 72.7 (62.9-81.2) | 72.2 (54.8-85.8) | 87.8 (78.7-94.0) | 49.1 (35.1-63.2) | 0.391 (0.235-0.556) | 72.6 (65.1-80.1) |
| N-MID change (ng/mL) | 0.764 (0.684-0.833) | < 0.001 | −5.65 | 43.4 (33.5-53.8) | 97.2 (85.5-99.9) | 97.7 (88.0-99.9) | 38.5 (28.4-49.2) | 0.274 (0.179-0.379) | 57.8 (49.5-66.1) |
| 1 y P1NP (ng/mL) | 0.803 (0.726-0.866) | < 0.001 | 33.66 | 89.9 (82.2-95.0) | 58.3 (40.8-74.5) | 85.6 (77.3-91.7) | 67.7 (48.6-83.3) | 0.505 (0.323-0.671) | 81.5 (75.0-88.1) |
| P1NP change (ng/mL) | 0.768 (0.688-0.837) | < 0.001 | −9.12 | 57.6 (47.2-67.5) | 91.7 (77.5-98.2) | 95.0 (86.1-99.0) | 44.0 (32.5-55.9) | 0.366 (0.233-0.498) | 66.7 (58.8-74.7) |
| 1 y β-CTX (ng/mL) | 0.753 (0.671-0.823) | < 0.001 | 0.238 | 86.9 (78.6-92.8) | 61.1 (43.5-76.9) | 86.0 (77.6-92.1) | 62.9 (44.9-78.5) | 0.484 (0.295-0.639) | 80.0 (73.3-86.7) |
| β-CTX change (ng/mL) | 0.753 (0.672-0.823) | < 0.001 | −0.111 | 51.5 (41.3-61.7) | 86.1 (70.5-95.3) | 91.1 (80.4-97.0) | 39.2 (28.4-50.9) | 0.273 (0.149-0.399) | 60.7 (52.5-68.9) |
| Phosphorus change (mmol/L) | 0.623 (0.536-0.705) | 0.029 | −0.04 | 60.6 (50.3-70.3) | 63.9 (46.2-79.2) | 82.2 (71.5-90.2) | 37.1 (25.2-50.3) | 0.199 (0.038-0.351) | 61.5 (53.3-69.7) |
Data are presented as value, value (95% CI) or % (95% CI). P value < 0.05 was considered to indicate a statistically significant difference (highlighted in bold).
AUC, area under the curve; BMD, bone mineral density; β-CTX, β-C-terminal telopeptide of type I collagen; CI, confidence interval; DE, diagnostic efficiency; N-NID, N-terminal middle segment osteocalcin; NPV, negative predictive value; PPV, positive predictive value; P1NP, propeptide of type I procollagen.