Simple Disease Activity Index (SDAI) for Rheumatoid Arthritis

Why Use

The Simplidied Disease Activity Index (SDAI) provides an excellent overview of a patient's disease severity (it correlates closely with the CDAI which does not require laboratory data) and the DAS-28 . The SDAI can also help guide therapy based on severity of disease.

When to Use

All patients with rheumatoid arthritis. Reassessing patients after starting a new medication for RA.

Formula

Pearls / Pitfalls

Assessment of disease activity in rheumatoid arthritis (RA) should be viewed as a dynamic, on-going process; many experts recommend assessing it at every patient visit. Early treatment is important for optimal RA outcomes, and the SDAI can help give a gestalt view of a patient's disease severity and activity. The Clinical Disease Activity Index (CDAI) provides similar information and correlates well but without the need for laboratory data (CRP).

Management

Refer to ACR guidelines for treatment of rheumatoid arthritis.

Critical Actions

Patients with high activity scores should receive early and aggressive RA medications with close follow-up, as attaining low activity or remission-level scores may prevent disease progression and disability.

More Information

SDAI Disease Severity ≤3.3 Remission >3.3-11.0 Low >11.0-26.0 Moderate >26.0 High