Development and validation of a Behçet's Disease Damage Index for adults with BD: An Explicit, Composite and Rated (ECR) tool

Background: Behçet's disease (BD) is a chronic multisystem variable vessel vasculitis. Disease damage is irreversible and permanent. Validated tools evaluating damage are limited. Enhancements in the clinical treatment of vasculitis will take place from the development of refined and exclusive indices for individual vasculitic syndromes including BD and attempting their international validation. Objectives: This aim was to develop and validate a simple BD Damage Index (BDI). Methods: This was a nationwide study including 1252 BD patients. The work consisted of 3 stages. Stage 1: items generation for score content. Stage 2: items selection for the draft score was performed by an expert rheumatologist. Stage 3: the content validity of the draft score was assessed and BDI, Vasculitis Damage Index (VDI), Antineutrophil cytoplasmic antibody-associated Vasculitis Index of Damage (AVID) and Combined Damage Assessment Index (CDAI) were calculated and compared. Results: The mean age of the BD patients was 36.1 ± 9.9 years. Stages 1 and 2 resulted in a BDI instrument containing 73 items with a maximum score of 100. Stage 3, the VDI, CDAI, AVID, and BDI were 2.9 ± 2.2, 3.1 ± 2.3, 3.1 ± 2.3 and 5.1 ± 2.9, respectively. High correlations (r =.9) between comparable damage scores assured acceptable concurrent validity. Conclusion: The proposed BDI represents a new robust and potentially useful tool when dealing with BD chronic status.