Table 6.
Predictive value for the progression from UA to RA within one year by location of erosive joints and cutoff of at least two erosive joints
| Location of erosions | n | PPV | (95% CI) | NPV | (95% CI) | Specificity | (95% CI) | Sensitivity | (95% CI) | LR+ | LR- | AUC (SEM) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wrist | 7 | 63.6 | 32-88 | 69.8 | 66-74 | 98.9 | 97-100 | 4.4 | 2-9 | 3.9 | 0.97 | 0.52 (0.028) |
| MCP | 5 | 38.5 | 15-68 | 69.3 | 65-73 | 97.8 | 95-99 | 3.1 | 1-8 | 1.4 | 0.99 | 0.50 (0.028) |
| PIP | 5 | 55.6 | 23-85 | 69.5 | 65-73 | 98.9 | 97-100 | 3.1 | 1-8 | 2.8 | 0.98 | 0.51 (0.028) |
| MTP | 23 | 67.6 | 5-9 | 71.6 | 67-76 | 96.6 | 94-98 | 14.4 | 10-21 | 4.3 | 0.88 | 0.56 (0.028) |
n = number of UA patients positive for this cutoff.
AUC = area under the curve; CI = confidence interval; LR+ = positive likelihood ratio; LR- = negative likelihood ratio; MCP = metacarpo-phalangeal joint; MTP = metatarso-phalangeal joint; NPV = negative predictive value; PIP = proximal inter-phalangeal joint; PPV = positive predictive value; RA = rheumatoid arthritis; SEM = standard error of measurement; UA = undifferentiated arthritis.