The CDAI is a useful clinical composite score for following patients with rheumatoid arthritis.
CDAI = SJC(28) + TJC(28) + PGA + EGA
- SJC(28): Swollen 28-Joint Count (shoulders, elbows, wrists, MCPs, PIPs including thumb IP, knees)
- TJC(28): Tender 28-Joint Count (shoulders, elbows, wrists, MCPs, PIPs including thumb IP, knees)
- PGA: Patient Global disease Activity (patient’s self assessment of overall RA disease activity on a scale 1-10 where 10 is maximal activity)
- EGA: Evaluator’s Global disease Activity (evaluator’s assessment of overall RA disease activity on a scale 1-10 where 10 is maximal activity)
Interpretation
| Remission | CDAI ≤ 2.8 |
| Low Disease Activity | CDAI > 2.8 and ≤ 10 |
| Moderate Disease Activity | CDAI > 10 and ≤ 22 |
| High Disease Activity | CDAI > 22 |
A CDAI reduction of 6.5 represents moderate improvement.
Deficiencies
- Does not include the ankles/feet
- Does not include inflammatory markers (although this is what makes it a quick and useful clinical tool)