Background: Predicting the outcome of ANCA-associated vasculitis (AAV) is a difficult task. One of the most promising prognostic scores, the ANCA Renal Risk Score (ARRS), has recently been updated and renamed to ANCA Kidney Risk Score (AKRiS). We wanted to test its performance in our population.
Methods: 164 patients were included and categorized in subgroups analogous to that of both scores. Multivariable logistic regression analysis was applied to assess the risk of renal failure. Additionally, baseline data and outcome were compared between the subgroups of each score to retrieve useful clinical information.
Results: Stratified by AKRiS risk category, the proportions of patients who developed end-stage kidney disease (ESKD) at 36 months were 9.8%, 29.1%, 63.0%, and 83.3%, respectively (p < 0.001).Those belonging to the higher risk groups showed more pronounced proteinuria and anemia at diagnosis (p=0.001, p<0.001, respectively). Although our patients exhibited a more severe disease phenotype than those of AARS and AKRiS, both scores performed equally well: The Harrell´s C Index was similar (0.8381 vs. 0.8337). Beyond that, we found differences and similarities in the risk associations between the subgroups of both scores and disease activity or patient outcome, with some of them being described for the first time. For example, there was a higher risk of renal failure with anemia but not with C-reactive protein and the Birmingham Vasculitis Activity Score (BVAS) and an increased incidence of relapsing disease in the lower risk categories of ARRS.
Conclusion: Here, we present the first external AKRiS validation confirming the improved ESKD prediction of the revised score in our cohort. Furthermore, we highlighted associations between risc score categories and patient mortality or vasculitis relapse.
Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Society of Nephrology.