Background Behcet's Syndrome Activity Scale (BSAS), a patient reported outcome measure for Behcet's syndrome, has been validated for routine clincial care and have been shown to differentiate active treatment from placebo in clinical trials. Currently, there are no identified thresholds for disease activity levels for BSAS.
Objectives To determine resmission, low, moderate and high disease activity level threshold scores for BSAS.
Methods Behcet's patients seen at the NYU Behcet's Center had their demographic, clinical features and outcomes data abstracted. Confirmed Behcet's diagnosis was determined if ISG criteria were met at any time during the course of observation. Concordance correlation was estimated between the BSAS and the RAPID3; both outcomes were scaled to [0-100]. Proposed BSAS severity categories are as: Near-Remission = [0-10), Low = [10-30), Moderate=[30-60), and High = [60-100]. Weighted Kappa statistics were estimated between BSAS and RAPID3 severity categories. RAPID3 categories were based upon published1 as well as matching the proposed BSAS severity categories.
Results First observation data on 832 subjects were abstracted for this analysis. 504 (63%) met ISG criteria for Behcet's, 616 (74%) were female with an average age of 35 years (±13.8). Concordance between BSAS and RAPID3 was moderate (CCC =0.518). BSAS severity categories classified 7% Near-Remission, 24% Low, 48% Moderate, and 21% of the study population as High disease severity (Table). Published RAPID3 categories classified 44% of subjects as High, while matching RAPID3 categories only classified 20%. Agreement between categories was moderate for both RAPID3 classifications.
Conclusions BSAS, a patient reported outcome measure for Behcet's syndrome, correlates well with other composite indices of disease activity. Proposed cut off points for near-remission, low, moderate and high activity for BSAS may be used in clinical care for a “treat-to-target” approach to Behcet's treatment.
Pincus T, Swearingen CJ, Bergman M, Yazici Y. J Rheumatol 2008 Nov;35(11):2136-47.
Disclosure of Interest Y. Yazici Grant/research support from: BMS, Celgene, Genentech, Consultant for: BMS, Celgene, H. Bernstein: None declared, C. Swearingen: None declared