Comparison of the Birmingham Vasculitis Activity Score and the Five‐Factor Score to Assess Survival in Antineutrophil Cytoplasmic Antibody–Associated Vasculitis: A Study of 550 Patients From Spain (REVAS Registry)

Abstract

Objective to compare the accuracy of Birmingham Vasculitis score (BVAS) v.3, and Five Factors Score (FFS) v.1996 and v.2009, to assess survival in ANCA‐associated Vasculitis (AAV). Methods 550 patients with AAV (41.1% GPA, 37.3% MPA, 21.6% EGPA) diagnosed between 1990‐2016 were analyzed. ROC curves and multivariable Cox analysis were used to assess the relationships between the outcome and the different scores. Results Overall mortality was 33.1%. The mean BVAS at diagnosis was 17.96±7.82, and was significantly higher in non‐survivors than in survivors (20.0±8.14 vs. 16.95±7.47, p<0.001). The mean 1996FFS and 2009FFS were 0.81±0.94 and 1.47±1.16, respectively, and were significantly higher in non‐survivors than in survivors (1.17±1.07 vs. 0.63±0.81, p<0.001; 2.13±1.09 vs. 1.15±1.05, p<0.001). Mortality rates increased accordingly to the different 1996FFS and 2009FFS categories. In multivariate analysis BVAS, 1996FFS and 2009FFS were significantly related to death (p=0.007, p=0.020, p<0.001), but the stronger predictor was the 2009FFS (HR 2.9, 2.4‐3.6). When the accuracy of BVAS, 1996FFS and 2009FFS to predict survival was compared in the global cohort, ROC analysis yielded AUC values of 0.60, 0.65 and 0.74, respectively, indicating that 2009FFS had the best performance. Similar results were obtained when comparing these scores in patients diagnosed before and after 2001, and assessing the 1‐year, 5‐years and long‐term mortality. Correlation among BVAS and 1996FFS was modest (r=0.49, p<0.001), but higher than between BVAS and 2009FFS (r=0.28, p<0.001). Conclusion BVAS and FFS are useful to predict survival in AAV, but 2009FFS has the best prognostic accuracy at any point of the disease course. Significance and innovation This is the first study comparing the BVAS, 1996FFS and 2009FFS accuracy to assess survival in patients with AAV, and the first to validate 2009FFS in these patients.