(HealthDay)—For patients with rheumatoid arthritis (RA), the performances of the Clinical Disease Activity Index (CDAI) and Simplified Disease Activity Index (SDAI) appear to be better than that of the Disease Assessment Score of 28 joints—C-reactive protein (DAS-28-CRP), according to a study published online June 12 in the International Journal of Rheumatic Diseases.

Pooja Dhaon, M.D., from Hind Institute of Medical Sciences in Safedabad, India, and colleagues included 135 patients with RA in a prospective study. The authors assessed disease activity at baseline and every six weeks for 24 weeks by DAS-28-CRP, CDAI, and SDAI. Based on pre-defined cut-offs, patients were classified into groups of remission, low activity, moderate activity, and high activity.

The researchers found that at baseline there was an excellent positive correlation between DAS-28-CRP and both CDAI (linear weighted κ, 0.545) and SDAI (linear weighted κ, 0.689). At the final visit there was moderate agreement between DAS-28-CRP and CDAI (linear weighted κ, 0.458) and between SDAI and DAS-28-CRP (linear weighted κ, 0.470). At baseline and the final visit, the correlation between CDAI and SDAI remained excellent. Significantly more residual disease activity was seen for patients in remission as per DAS-28-CRP versus SDAI and CDAI remission criteria.

"SDAI- and CDAI-based remission criteria seem to be better than DAS-28-CRP-based remission criteria," the authors write.

More information: Abstract
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