Validation of the Birmingham Vasculitis Activity Score (Version 3)

Background: The Birmingham Vasculitis Activity Score is a clinical tool to quantify disease activity in systemic vasculitis. Following its extensive use, a previous version of BVAS has been revised to improve the face validity and the feasibility. Changes were made and approved by an expert committee. Objective: To validate the third version of the Birmingham Vasculitis Activity Score (BVAS version 3) Methods: In a series of prospective, multi-centre studies, different aspects of the BVAS (version 3) were validated in patients with systemic vasculitis. The data collection was done using standardized data entry forms. The studies were approved by local ethics committees. The recruitment of controls was approved by the local clinical audit and effectiveness department. Results: The convergent validity was established by correlating the BVAS (version 3) to the physician’s treatment decision (Spearman's ρ 0.66, 95% CI 0.59-0.72), BVAS1 of version 2 (ρ 0.94, 95% CI 0.92-0.96), BVAS2 of version 2 in patients with persistent disease (ρ 0.60, 95% CI 0.21-0.83), C-reactive protein levels (ρ 0.43, 95% CI 0.31-0.54), physician's global assessment (ρ 0.91, 95% CI 0.89-0.93), and vasculitis activity index (ρ 0.88, 95%CI 0.86-0.91). The BVAS (version 3) was reproducible and repeatable (intra-class correlation coefficients were 0.96 (95%CI 0.95-0.97) and 0.96 (95%CI 0.92-0.97) respectively). The BVAS (version 3) was sensitive to changing disease status with a fall of 16.9 (95% CI 14.8-18.9) units (P