Maxime Verhoeven

193 Development and validation of DAS-OST Diagnostic value Overall discrimination and diagnostic accuracy measures of DAS-OST indices for DAS28- based and Boolean remission, LDA and HDA are shown in Table 4. Discriminatory ability for DAS-OST value was generally high, ranging from 0.86 to 0.97 for indices including VAS in internal validation, and from 0.92 to 0.95 in external validation. Unfortunately, the AU-ROC for Boolean remission could not be calculated in the external validation cohort, since no patient was in this disease state. In line with agreement and measurement error results, AU-ROC and diagnostic accuracy measures of DAS-OST without patient VAS were lower. Sensitivity and specificity for all disease states were in general good, but sensitivity for HDA was lower and 95% confidence interval wider, compared to DAS28-based remission and LDA, Table 4. Using the DAS-OST without patient VAS cut-off, no patient was classified into the disease state HDA. 10