DAS Scores Using C-Reactive Protein (DAS CRP)

 

Parameters:

(1) Ritchie score – range 0 to 46

(2) number of swollen joints- range 0 to 44

(3) C-reactive protein (CRP) in mg/L

(4) general health status using a 100 mm visual analogue scale (VAS) – range 0 to 100, with 100 indicating worst possible health imaginable

 

DAS score using 4 variables =

= (0.53938 * (SQRT(Ritchie score))) + (0.06465 * (number of swollen joints)) + (0.17 * LN(CRP+1)) + (0.00722 * (general health VAS score)) + 0.45

 

DAS score using 3 variables =

= (0.53938 * (SQRT(Ritchie score))) + (0.06465 * (number of swollen joints)) + (0.17 * LN(CRP+1)) + 0.65

 

where:

• Adding 1 to the CRP avoids LN(0).

 

Interpretation:

• minimum score: 0 (no disease activity)

• maximum score: around 8.16

• The higher the score, the greater the disease activity.