Skip to main content

Table 4 Composite measures of disease activity used in rheumatoid arthritis: components, calculation formula, and range of results

From: 2017 recommendations of the Brazilian Society of Rheumatology for the pharmacological treatment of rheumatoid arthritis

Components SDAI CDAI DAS28 (with 4 variables)
Number of swollen joints (0–28)
Simple sum
(0–28)
Simple sum
Square root of the simple sum
Number of painful joints (0–28)
Simple sum
(0–28)
Simple sum
Square root of the simple sum
Acute phase reagents CRP
(0.1–10 mg/dL)
ESR 2–100 mm
or CRP 0.1–10 mg/dL logarithmic transformation
Global health assessment
(Patient)
  0–100 mm
Assessment of disease activity
(Patient)
(0–10 cm) (0–10 cm)
Assessment of disease activity
(Examiner)
(0–10 cm) (0–10 cm)
Total index Simple sum Simple sum Calculation formula (requires a calculator)
Index variation (0.1–86.0) (0–76) (0.49–9.07)
  1. CDAI, clinical disease activity index; DAS28, disease activity index (28 joints); CRP, C-reactive protein; SDAI, simplified disease activity index; ESR, erythrocyte sedimentation rate. Assuming a variation of 2 to 100 mm/h for ESR and of 0.1 to 10 mg/dL for CRP [6, 142].