Comparison of existing disease activity indices in the follow-up of patients with Behcet's disease

Abstract

The objective of this study was to determine the concordance between the Iranian Behcet's disease dynamic activity measure (IBDDAM) or the Behcet's disease current activity form (BDCAF) and expert physician global assessment (PGA) in the evaluation of disease activity changes in Behcet's disease (BD). In a prospective study, 117 consecutive patients with BD were evaluated in their two consecutive follow-up visits by IBDDAM and BDCAF. The change in disease activity was determined (increased, unchanged or decreased) according to the PGA. We used receiver operating characteristic (ROC) curve to determine an appropriate cutoff point for disease activity change. Comparison was made by Stata and kappa analysis. Comparing the area under the ROC curve showed a significant difference between IBDDAM and BDCAF (p < 0.03). The difference was more significant between nonocular IBDDAM and BDCAF (p < 0.002). Better concordance was also observed for IBDDAM (nonocular and total) with PGA than BDCAF. The difference was not significant for ocular IBDDAM. The best cutoff point for nonocular IBDDAM was 0.45, for ocular IBDDAM was 3.5, and for BDCAF was 1 point. IBDDAM was the preferred method for the evaluation of disease activity change in patients with BD (without ocular involvement) considering a change of at least 0.45.