RA disease activity measures offer easy, practical alternative

Less complex disease activity measures for evaluating patients with rheumatoid arthritis (RA) correlate well with the C-reactive protein–based Disease Activity Score 28 (DAS28-CRP4) and may provide physicians in office practices with practical, easy-to-use tools. If the Clinical Disease Activity Index (CDAI) and the Routine Assessment of Patient Index Data (RAPID5) are found to correlate well with the DAS, they would decrease costs associated with laboratory testing.

Working with 740 patients, Sullivan and associates examined the correlation between the DAS28-CRP4 and 5 disease activity indices: the Multi-Dimensional Health Assessment Questionnaire, the Rheumatoid Arthritis Disease Activity Index, and the Global Arthritis Score as well as the CDAI and the RAPID5. Baseline assessment included clinical information, disease activity, comorbidity, laboratory testing, and hand radiographs. DAS28-CRP4 data were obtained at baseline and 1 year, and anticyclic citrullinated peptide status and change were evaluated at 1 year. Pairwise correlations were calculated for each index.

The CDAI and RAPID5 indices correlated best with the DAS28-CRP4 at baseline and at 1 year of change. They also agreed with each other at these points.

The authors noted that more validation of these disease activity indices is needed before they can replace DAS28-CRP4 scores in clinical trials.