Table 1 Comparison of composite measures for assessment of remission and disease activity in rheumatoid arthritis*
Elements | DAS 28 | SDAI | CDAI | Boolean approach (remission only) |
|---|---|---|---|---|
Number of swollen joints (SJC) | 0–28 (square root transformed) | 0–28 (simple count) | 0–28 (simple count) | ≤ 1 |
Number of tender joints (TJC) | 0–28 (square root transformed) | 0–28 (simple count) | 0–28 (simple count) | ≤ 1 |
Patient global assessment (PtGA) | 0–100 VAS in mm | 0–10 scale | 0–10 scale | ≤ 1 (0–10 scale) |
Physician global assessment (PhGA) | – | 0–10 scale | 0–10 scale | – |
Acute phase reactant | ESR or CRP log transformed | CRP in mg/dl (0–10) | – | CRP ≤ 1 mg/dl |
Total index | 0–9.4 No immediate scoring, calculator required | 0–86.0 No immediate scoring due to CRP, simple calculation | 0–76.0 Immediate scoring, simple calculation | – |
Formula | 0.56 × √(28TJC) + 0.28 × √(28SJC) + 0.70 × ln(ESR) + 0.014 × PtGA or 0.56 × √(28TJC) + 0.28 × √(28SJC) + 0.36 × ln(CRP + 1) + 0.014 × PtGA + 0.96 | 28SJC + 28TJC + PhGA + PtGA + CRP | 28SJC + 28TJC + PhGA + PtGA | – |
Cut-off | ||||
Remission |  < 2.6 | ≤ 3.3 | ≤ 2.8 | At any time point, patient must satisfy the above cut-offs |
Low disease activity |  < 3.2 | ≤ 11.0 | ≤ 10.0 | – |