Table 4.
Accuracy of phalangeal RA in predicting osteoporosis
| Phalangeal RA (n = 245) | Youden 1 | UK-NOS triage approach 90% certainty level | UK-NOS triage approach 95% certainty level |
|---|---|---|---|
| RA T-score Upper/lower cutoff | -2.22 | -0.65/–2.95 | 0.28/–3.32 |
| Sensitivity (95% CI) | 67.6 (57.9–76.3) | 90.7 (83.6–95.5) | 95.4 (89.5–98.5) |
| Specificity (95% CI) | 78.1 (70.2–84.7) | 90.5 (84.3–94.9) | 95.6 (90.7–98.4) |
| PPV (95% CI) | 70.9 (61.1–79.4) | 75.0 (61.1–86) | 82.9 (66.4–93.4) |
| NPV (95% CI) | 75.4 (67.4–82.2) | 81.1 (68–90.6) | 77.3 (54.6–92.2) |
| False negative n (%) | 35 (14.3) | 10 (4.1) | 5 (2.0) |
| False positive n (%) | 30 (12.2) | 13 (5.3) | 6 (2.5) |
| DXA scans avoided n (%) | NA | 105 (42.9) | 57 (23.3) |
Accuracy of phalangeal RA in predicting osteoporosis applying the optimal cutoff and UK-NOS triage approach at 90% and 95% certainty levels. 1the optimal cutoff calculated according the Youden index [30]. Abbreviations: RA Radiographic Absorptiometry, UK-NOS United Kingdom National Osteoporosis Society, PPV Positive Predictive Value, NPV Negative Predictive Value, DXA Dual Energy X-ray Absorptiometry, CI Confidence Interval, NA not available.