Maxime Verhoeven

201 Development and validation of DAS-OST Supplementary Table S2 Number of patients classified per disease activity state based on DAS28 and DAS-OST in internal validation. Remission LDA MDA HDA misclassification per disease activity state DAS-OST remission 542 43 24 0 11% DAS-OST LDA 89 52 49 1 73% DAS-OST MDA 17 83 178 18 40% DAS-OST HDA 0 0 6 18 25% overestimation 12% underestimation 17% total misclassification 29% weighted Cohen’s Kappa* 0.65 Internal validation cohort consisted of 1120 observations from MMC cohort, not used in development cohort. DAS-OST consisted of total OST-score, gender, ESR and patient VAS. *weights for the weighted Cohen’s Kappa were: no difference between category: weight=0; difference is 1 category (next to reference category): weight=1; difference is 2 categories (next to reference category): weight=2; difference is 3 categories (next to reference category): weight=3. LDA= low disease activity; MDA= moderate disease activity; HDA= high disease activity. Supplementary Table S3 Number of patients classified per disease activity state based on DAS28 and DAS-OST in external validation. Remission LDA MDA HDA misclassification per disease activity state DAS-OST remission 34 6 3 0 21% DAS-OST LDA 9 4 14 1 86% DAS-OST MDA 0 5 35 19 41% DAS-OST HDA 0 0 4 16 20% overestimation 29% underestimation 12% total misclassification 41% weighted Cohen’s Kappa* 0.64 External validation cohort consisted of 151 observations from the ACURA cohort. DAS-OST consisted of total OST-score, gender, ESR and patient VAS. *weights for the weighted Cohen’s Kappa were: no difference between categories: weight=0; difference is 1 category (next to reference category): weight=1; difference is 2 categories (next to reference category): weight=2; difference is 3 categories (next to reference category): weight=3. LDA= low disease activity; MDA= moderate disease activity; HDA= high disease activity. 10