Maxime Verhoeven

208 Chapter 11 0.55-0.63), respectively, Table 2. The discriminative ability was statistically significantly higher for DAS28, compared to DAS-OST: ∆AU-ROC 0.10, 95%CI 0.08-0.12, whereas it was statistically significantly higher for DAS-OST, compared to the OST-score: ∆AU-ROC 0.19, 95%CI 0.14-0.23, see Table 2 and Figure 1. Table 2 Area under the receiver operating characteristics curves for individual models and comparisons. ROC model AU-ROC (95%CI) p-value Individual model DAS28 0.88 (0.85 – 0.90) <0.01 DAS-OST 0.78 (0.75 – 0.81) <0.01 OST-score 0.59 (0.55 – 0.63) <0.01 Comparisons Difference: DAS28 minus DAS-OST 0.10 (0.08 – 0.12) <0.01 Difference: DAS-OST minus OST-score 0.19 (0.14 – 0.23) <0.01 AU-ROC= Area under the receiver operating characteristics curve; CI= confidence interval; DAS28= disease activity score assessing 28 joints; DAS-OST= disease activity using optical spectral transmission; OST- score= optical spectral transmission score. Figure 1 Receiver operating characteristics curves with 95%confidence areas of sensitivity. The classification as ‘not active disease’ according to the clinical interpretation was used as reference. DAS28= disease activity score assessing 28 joints; DAS-OST= disease activity using optical spectral transmission; OST-score= optical spectral transmission score.