Ankylosing Spondylitis Disease Activity Score

 

NOTES:

(1) Certain features of the ASDAS resemble the Ankylosing Spondylitis Disease Activity Score (AS-DAS) of Creemers et al (above).

(2) Some items are derived from the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI, above).

 

Parameters:

(1) back pain (using BASDAI question 2)

(2) duration of morning stiffness (using BASDAI question 6)

(3) patient global status

(4) peripheral pain and swelling (using BASDAI question 3)

(5) serum C-reactive protein (CRP) in mg/L

Response for Items 1-4	VAS Score
none	0
very severe (worst imaginable)	10

 

ASDAS =

= (0.121 * (points for back pain)) + (0.058 * (points for duration of morning stiffness)) + (0.110 * (points for global status)) + (0.073 * (points for peripheral pain and swelling)) + (0.579 * LN((CRP) + 1))

 

where:

• Adding 1 to the CRP prevents LN(0).

 

Interpretation:

• minimum ASDAS: 0

• The summation for the first 4 items at maximum points is 3.62. A CRP of 100 mg/L would add 2.67 to the score. Thus the maximum ASDAS would be between 6 and 7.

• An ASDAS of 4.5 corresponds to a physician's global assessment of 6.

• An ASDAS of 3.5 corresponds to a physician's global assessment of at least 4.