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

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)