Table 1.

Formulae and cut-off points for disease severity states for ASDAS and SASDAS.

ASDASSASDAS
ASDAS-ESRASDAS-CRPSASDAS-ESRSASDAS-CRP
Formula(0.08 × back pain) + (0.07 × duration morning stiffness) + (0.11 × patient global) + (0.09 × peripheral pain/swelling) + (0.29 × √ESR)(0.12 × back pain) + (0.06 × duration morning stiffness) + (0.11 × patient global) + (0.07 × peripheral pain/swelling) + (0.58 × Ln(CRP+1))(back pain) + (duration morning stiffness) + (patient global) + (peripheral pain/swelling) + (ESR/10)(back pain) + (duration morning stiffness) + (patient global) + (peripheral pain/swelling) + (CRP)
Cut-off point0-1.2: inactive disease
1.3-2.0: lowa disease activity
2.1-3.5: high disease activity
> 3.5: very high disease activity
0-7.8: inactive disease
7.9-13.8: moderate disease activity
13.9-27.6: high disease activity
> 27.6: very high disease activity
0-10.4: inactive disease
10.5-19.0: moderate disease activity
19.1-36.0: high disease activity
> 36.0: very high disease activity
  • aThe ASAS group in 2018 changed the nomenclature of ASDAS disease activity states by replacing “moderate” with “low,” without changing the cut-offs.11 For SASDAS, this change has not yet been formalized. ASAS: Assessment of SpondyloArthritis international Society; ASDAS: Axial Spondyloarthritis Disease Activity Score; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; SASDAS: Simplified Axial Spondyloarthritis Disease Activity Score.