Disease activity score

Disease activity score, also called DAS28, is a measure widely used in measuring the response to treatment in rheumatoid arthritis.

Joints included in DAS28

Bilateral proximal interphalangeal joints total of 10 joints Bilateral metacarpophalangeal joints total of 10 Bilateral wrists total of 2, Bilateral elbows total of 2, Bilateral shoulders total of 2 and Bilateral knees total of 2.

What is measured in DAS28?

In any of the joints, tenderness upon touching which gives the TEN28 score and joint swelling of the joints which gives SW28 are counted.

Sed rate measurement

The erythrocyte sedimentation rate (ESR) is also measured.

Subjective assessment

The affected person makes a subjective assessment (SA) of disease activity during the preceding 7 days on a scale between 0 and 100, where 0 is "no activity" and 100 is "highest activity possible".

How is DAS28 calculated?

With the above parameters, DAS28 is calculated as:

From this, the disease activity of the affected person can be classified as follows:

Current DAS28		DAS28 decrease from initial value
		> 1.2	> 0.6 but ≤ 1.2	≤ 0.6
≤ 3.2	Inactive	Good improvement	Moderate improvement	No improvement
> 3.2 but ≤ 5.1	Moderate	Moderate improvement	Moderate improvement	No improvement
> 5.1	Very active	Moderate improvement	No improvement	No improvement

Clinical utility of DAS28 score

Although it gives a good indication of the disease activity, it is not always a reliable indicator of treatment effect.

Limitations of DAS28 score

One major limitation is that low-grade synovitis may be missed.

Also see

• ACR-EULAR Provisional Definition of Remission of Rheumatoid arthritis,
• Simplified Disease Activity Index and
• Clinical Disease Activity Index.
• Some scores do not require input from a healthcare professional and allow self-monitoring by the person, like Health Assessment Questionnaire Disability Index (HAQ-DI).