9.40. Disease Activity Score-28 (DAS28)

Warning

(¶+) Reproduction of this task/scale is not permitted (or such permission is not clear). This CamCOPS task is a data collection tool only, with no scale text (unless configured locally to use externally provided text that the hosting institution is legally permitted to use). Use it only in conjunction with a licensed copy of the original task. If your institution is entitled to use the task, you may install an add-on XML file on your server containing the required strings, to make the task fully functional, but you must provide this XML file and its contents yourself (it is outside the scope of CamCOPS).

Disease activity score for rheumatoid arthritis. The 28 refers to the number of joints in which disease activity is rated (bilaterally: shoulder, elbow, wrist, knee, 5 × MCP, 5 × PIP).

For each joint, “swollen?” and “tender?” are asked; there is a visual analogue rating scale (100 mm in length) for arthritis activity, plus an inflammatory marker. In the original DAS28 (sometimes termed the DAS28-ESR), this was ESR (erythrocyte sedimentation rate). An alternative is the CRP (C-reactive protein), in the DAS28-CRP.

  • t28 = number of tender joints, range [0, 28].
  • sw28 = number of swollen joints, range [0, 28].
  • The CRP units are mg/L and in the range [0, 300].
  • The ESR units are mm/hr and in the range [1, 300].
  • The VAS (visual analogue scale) units are mm, range [0, 100]. Low is inactive arthritis; high is extremely active arthritis.

DAS28 score = 0.56 × √(t28) + 0.28 × √(sw28) + 0.70 × ln(ESR) + 0.014 × VAS

DAS28-CRP score = 0.56 × √(t28) + 0.28 × √(sw28) + 0.36 × ln(CRP + 1) + 0.014 × VAS + 0.96.

These are the “4-variable” DAS scales (tenderness, swelling, inflammatory marker, VAS). There are different 3-variables scales too, without the VAS, not implemented here.

9.40.1. Intellectual property rights

9.40.2. History

9.40.3. Source