Table 1.
Model equations, sensitivity and specificity of selected final models
| Model number | Equation | Sensitivity, % | Specificity, % | |
|---|---|---|---|---|
| Radiographic progression (change in vdHS score) | ||||
| 1 | √(change in vdHS score) | = −1.61 + 0.433*log(power Doppler volume) + 0.220*√(baseline vdHS score) + 0.442*log(ESR) + 0.503*(gender) | 63.2 (95% CI 47.1, 79.2) | 80.9 (95% CI 69.2, 92.5) |
| 2 | √(change in vdHS score) | = −0.892 + 0.419*log(power Doppler volume) + 0.236*√(baseline vdHS score) + 0.402*log(ESR) | 67.6 (95% CI 51.7, 83.4) | 78.7 (95% CI 66.6, 90.9) |
| US progression (change in US erosions score) | ||||
| 3 | √(change in erosions score) | = −1.09 + 0.289*log(power Doppler volume) + 0.0180*(age) + 0.173*√(baseline erosion score) + 0.314*(gender) | 54.2 (95% CI 32.7, 75.7) | 96.7 (95% CI 92.1, 100.0a) |
aEstimated by the formula as >100%; rounded down to 100%. Power Doppler volume measured in cubic millimetres. Gender coded as 1 (female) or 2 (male). Age measured in years at the time of baseline visit. √: square root; *: multiplied; vdHS: van de Heijde–Sharp.