The influence of the definition of patient global assessment in assessment of disease activity according to the Disease Activity Score (DAS28) in rheumatoid arthritis.

Abstract

Patient global assessment (PGA) is one of the 4 items included in the Disease Activity Score (DAS28) for evaluation of activity of rheumatoid arthritis (RA). We studied the influence of the use of 3 different techniques of PGA on the assessment of disease activity. We evaluated 3 different DAS28 according to the technique of PGA in 108 patients with active RA before and after 12 weeks of etanercept therapy. The reliability (intraclass coefficient of correlation) between screening and baseline was very high and similar for the 3 DAS28. The percentage of patients in the different states of disease (from remission to higher disease activity) and the sensitivity to change across the 3 DAS28 scales were very similar. The different techniques of collection of PGA to be included in the DAS calculation yield similar results. However, an accepted, unequivocal technique should be encouraged in order to reduce heterogeneity in scoring DAS among patients with RA.