Table 5.
Predictive value for the progression from UA to RA within one year using different cut-off values for erosions in feet
| Number of erosive joints | n | PPV | (95% CI) | NPV | (95% CI) | Specificity | (95% CI) | Sensitivity | (95% CI) | LR+ | LR- | AUC (SEM) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ≥1 | 89 | 49 | 39-60 | 73 | 69-77 | 87 | 84-91 | 28 | 21-34 | 2.2 | 0.83 | 0.57 (0.028) |
| ≥2 | 42 | 60 | 48-74 | 72 | 68-76 | 95 | 93-98 | 16 | 10-21 | 3.3 | 0.89 | 0.55 (0.028) |
| ≥3 | 18 | 67 | 45-88 | 70 | 66-74 | 98 | 97-100 | 8 | 3-12 | 4.5 | 0.94 | 0.53 (0.028) |
| ≥4 | 9 | 67 | 36-98 | 70 | 66-74 | 99 | 98-100 | 4 | 1-7 | 4.5 | 0.97 | 0.52 (0.028) |
| ≥5 | 5 | 80 | 45-115 | 70 | 66-74 | 100 | 99-100 | 3 | 0-5 | 8.9 | 0.98 | 0.51 (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; NPV = negative predictive value; PPV = positive predictive value; RA = rheumatoid arthritis; SEM = standard error of measurement; UA = undifferentiated arthritis.