Elements of composite indices for evaluation of disease activity in rheumatoid arthritis4. Values in parentheses are ranges.
| Elements | SDAI | CDAI | DAS | DAS28 |
|---|---|---|---|---|
| Number of swollen joints | Simple count (0–28) | Simple Count (0–28)(0–2.86) | More extensive joint counts transformed (0–1.48) | Simple count, square root |
| Number of tender joints | Simple count (0–28) | Simple Count (0–28) | Ritchie Index: graded joint counts; square root transformed (0–4.77) | Simple count; square root transformed (0–2.96) |
| Acute-phase reactants | CRP in mg/dl (0.1–10.0) | — | ESR, log transformed (0.23–1.51)* | ESR, log transformed (0.49–3.22)* |
| Patient global health | — | — | VAS in mm (0–0.72)* | VAS in mm (0–1.40)* |
| Patient global disease activity | VAS in cm (0–10.0) | VAS in cm (0–10.0) | — | — |
| Evaluator global disease activity | VAS in cm (0–10.0) | VAS in cm (0–10.0) | — | — |
| Total Index | No immediate scoring due to CRP; simple calculation possible (0.1–86.0) | Immediate scoring possible; simple calculation possible (0–76.0) | No immediate scoring due to ESR; calculator required (0.23–9.87) | No immediate scoring due to ESR; calculator required (0.49–9.07) |
↵* The DAS and DAS28 formulae have also been modified to include CRP instead of ESR, and to substitute the patient global health by a constant. These versions are less commonly used and not well validated. SDAI: Simplified Disease Activity Index; CDAI: Clinical DAI; DAS: Disease Activity Score; CRP: C-reactive protein; ESR: erythrocyte sedimentaion rate. Reprinted from J Clin Exp Rheumatol 2005;23 Suppl 39:S100–8 with permission.