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Table 1 Formulae to calculate the different DAS and SDAI score

From: DAS28 best reflects the physician's clinical judgment of response to infliximab therapy in rheumatoid arthritis patients: validation of the DAS28 score in patients under infliximab treatment

Score Formula AUC (95% CI) Sens at 95% spec, % (95% CI)
DAS28 0.56*sqrt(28TJC) + 0.28*sqrt(28SJC) + 0.70*ln(ESR) + 0.014*pt global VAS 0.840 (0.791–0.889) 42.5 (36.9–48.1)
DAS28-3 [0.56*sqrt(28TJC) + 0.28*sqrt(28SJC) + 0.70*ln(ESR)]*1.08 + 0.16 0.815 (0.763–0.868) 37.8 (32.3–43.3)
DAS28-CRP 0.56*sqrt(28TJC) + 0.28*sqrt(28SJC) + 0.36*ln(CRP+1) + 0.014* pt global VAS + 0.96 0.829 (0.782–0.876) 35.8 (30.4–41.2)
DAS28-CRP-3 [0.56*sqrt(28TJC) + 0.28*sqrt(28SJC) + 0.36*ln(CRP+1)] * 1.10 + 1.15 0.806 (0.755–0.858) 28.9 (23.8–33.9)
SDAI 28TJC + 28SJC + CRP/10 + pt global VAS/10 + phys global VAS/10 0.824 (0.776–0.873) 40.7 (35.1–46.2)
CDAI 28TJC + 28SJC + pt global VAS/10 + phys global VAS/10 0.821 (0.772–0.870) 37.8 (32.3–43.2)
  1. DAS28-3 and DAS28-CRP-3 are the DAS28 and DAS28-CRP scores calculated without the patient's global disease activity VAS. AUC, area under the curve; CDAI, clinical disease activity score; CRP, C-reactive protein; DAS, disease activity score; ESR, erythrocyte sedimentation rate; phys, physician; pt, patient; SDAI, simplified disease activity score; SJC28, 28 swollen joint count; TJC28, 28 tender joint count; VAS, Visual Analogue Scale.