ToolsCalculators
Clinical Disease Activity Index (CDAI) for Rheumatoid Arthritis
Clinical Disease Activity Index (CDAI) for Rheumatoid Arthritis
Tender joint count (28-joint)
joints
Swollen joint count (28-joint)
joints
Patient global assessment of disease activity
0-10 cm visual analogue scale (0 = very well, 10 = very poor).
cm (0-10)
Evaluator (physician) global assessment of disease activity
0-10 cm visual analogue scale.
cm (0-10)
Complete the fields above to see the result.
When to use
- Bedside or office-based tracking of rheumatoid arthritis disease activity when no acute-phase reactant is immediately available.
- Treat-to-target monitoring, since it can be calculated instantly from the physical exam and two global assessments.
Formula
CDAI = tender joint count (28 joints) + swollen joint count (28 joints) + patient global assessment (0-10 cm VAS) + evaluator global assessment (0-10 cm VAS). Range 0-76. Remission <=2.8, low activity >2.8-10, moderate activity >10-22, high activity >22.
Pearls and pitfalls
- Does not require an ESR or CRP, so it can be calculated during the same visit and is unaffected by acute-phase reactant assay variability.
- Values track closely with SDAI despite omitting CRP, and both correlate well with DAS28.
References
- Aletaha D, Nell VP, Stamm T, et al. Acute phase reactants add little to composite disease activity indices for rheumatoid arthritis: validation of a clinical activity score. Arthritis Res Ther. 2005;7(4):R796-806.
- Aletaha D, Ward MM, Machold KP, et al. Remission and active disease in rheumatoid arthritis: defining criteria for disease activity states. Arthritis Rheum. 2005;52(9):2625-36.