Background: Comprehensive multi-system clinical assessment using the Birmingham Vasculitis Activity score (BVAS) is widely used in therapeutic studies of systemic vasculitis. Extensive use suggested a need to revise the instrument. The previous version of BVAS has been revised, according to usage and review by an expert committee.
Objective: To modify and validate version 3 of the BVAS in patients with systemic vasculitis. Methods: The new version of BVAS was tested in a prospective cross-sectional study of patients with vasculitis.
Results: The number of items was reduced from 66 to 56. The sub-scores for new/worse disease and persistent disease were unified. In 313 patients with systemic vasculitis, BVAS(v.3) correlated with 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 intra-class correlation coefficients for reproducibility and repeatability were 0.96 (95%CI 0.95-0.97) and 0.96 (95%CI 0.92-0.97) respectively. In 39 patients assessed at diagnosis and again at 3 months, the BVAS(v.3) fell by 17 (95% CI 15-19) units (P<0.001, paired t test).
Conclusion: BVAS(v.3) demonstrates convergence with BVAS(v.2), treatment decision, physician global assessment of disease activity, vasculitis activity index and CRP. It is repeatable, reproducible and sensitive to change. The new version of BVAS is validated for assessment of systemic vasculitis.