9.40. Disease Activity Score-28 (DAS28)

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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, constrained to be integer and in the range [0, 300].
  • The ESR units are mm/hr, constrained to be integer and in the range [1, 300].
  • The VAS 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.

9.40.1. Intellectual property rights

9.40.2. History

  • Prevoo ML, van ‘t Hof MA, Kuper HH, van Leeuwen MA, van de Putte LB, van Riel PL (1995). Modified disease activity scores that include twenty-eight-joint counts. Development and validation in a prospective longitudinal study of patients with rheumatoid arthritis. Arthritis Rheum. 38: 44-8. https://www.ncbi.nlm.nih.gov/pubmed/7818570

    [Original version using ESR.]

  • Fransen J, Welsing PMJ, de Keijzer RMH, van Riel PLCM (2003). Disease activity scores using C-reactive protein: CRP may replace ESR in the assessment of RA disease activity. Ann Rheum Dis 62(Suppl. 1): 151.

    [DAS-28-CRP source, according to Hensor et al. 2010 as below.]

  • Fleischmann RM, van der Heijde D, Gardiner PV, Szumski A, Marshall L, Bananis E (2017). DAS28-CRP and DAS28-ESR cut-offs for high disease activity in rheumatoid arthritis are not interchangeable. RMD Open 3: e000382. https://doi.org/10.1136/rmdopen-2016-000382. https://www.ncbi.nlm.nih.gov/pubmed/28255449.

    [Helpful review comparing DAS28-ESR and DAS28-CRP.]

  • Hensor EM, Emery P, Bingham SJ, Conaghan PG; YEAR Consortium (2010). Discrepancies in categorizing rheumatoid arthritis patients by DAS-28(ESR) and DAS-28(CRP): can they be reduced? Rheumatology (Oxford) 49: 1521-9. https://doi.org/10.1093/rheumatology/keq117. https://www.ncbi.nlm.nih.gov/pubmed/20435650.

    [Useful history.]

9.40.3. Source