What SDAI score represents Boolean remission equivalent?

SDAI ≤3.3 corresponds closely to ACR/EULAR Boolean remission; this threshold requires SJC28 ≤1, TJC28 ≤1, PGA ≤2, and CRP ≤1 mg/dL individually to meet Boolean criteria.

How is CRP added to SDAI?

CRP is added directly as mg/dL (not mg/L); e.g., CRP 0.5 mg/dL (5 mg/L) contributes 0.5 to SDAI; this makes SDAI slightly higher than CDAI by the CRP value; maximum CRP contribution is significant in highly inflamed states.

Which index is most sensitive for detecting treatment response?

All indices (DAS28, CDAI, SDAI) show comparable sensitivity to change; choice depends on practice preference; including CRP (SDAI/DAS28) may better reflect objective inflammation beyond joint counts.

Are SDAI and CDAI validated for psoriatic arthritis?

SDAI and CDAI were developed for RA but are used off-label in PsA; DAPSA (Disease Activity in PSoriatic Arthritis) uses similar approach validated specifically for PsA peripheral joint disease.

How often should DAS28/CDAI/SDAI be calculated in treat-to-target?

Monthly assessment until target reached; then every 3-6 months for stable patients; every visit for active disease; documented scores required for biologic prescription renewal and biosimilar switching decisions.

SDAI (Simplified Disease Activity Index) Calculator

Calculates SDAI for rheumatoid arthritis by summing swollen joint count, tender joint count, patient global, physician global, and CRP (mg/dL), with ACR/EULAR remission criteria comparison.

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Frequently Asked Questions

What SDAI score represents Boolean remission equivalent?

How is CRP added to SDAI?

Which index is most sensitive for detecting treatment response?

Are SDAI and CDAI validated for psoriatic arthritis?

How often should DAS28/CDAI/SDAI be calculated in treat-to-target?