Risk stratification for renal outcomes in ANCA-associated vasculitides using established scores and histopathological criteria

Journal of Nephrology, vol. 39, pp. 179–187

Abstract

BACKGROUND: Glomerulonephritis is a common, organ-threatening manifestation in ANCA-associated vasculitis (AAV). Various clinico-histological scores have been developed assessing the risk of kidney failure, including the simplified ANCA kidney risk score (AKRiS). METHODS: This retrospective study included 220 patients with biopsy-confirmed kidney involvement of granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) recruited from four tertiary European referral centers. We collected biometric and clinical baseline data, disease activity parameters, AKRiS classes and histomorphological features. We examined the occurrence of a composite endpoint (ie all-cause mortality or kidney failure defined as persistent estimated glomerular filtration rate [eGFR] decline <15 mL/min/1.73 m² or kidney replacement therapy after ≥6 months, respectively) within individual AKRiS and precursor risk classes. RESULTS: GPA and MPA patients exhibited largely comparable baseline characteristics and treatment regimens. Histological analysis revealed that MPA biopsies showed significantly more sclerosis, interstitial fibrosis and tubular atrophy (IFTA) than their GPA counterparts. Histologically, most patients fell into focal and mixed classes, which mainly transitioned into low- and medium-risk AKRiS categories. Higher risk classifications predominantly derived from crescentic and sclerotic classes. Patients categorized as medium risk in the precursor score most frequently transitioned to lower AKRiS scores. AKRiS stratification was superior to the ANCA Renal Risk Score (ARRS) in the prediction of adverse outcomes over the entire period (AUC 0.76, C-Index 0.899). CONCLUSIONS: The AKRiS score was found to be effective in predicting kidney failure and a strong composite kidney endpoint in a large European AAV cohort, despite slight differences in histological and event patterns between GPA and MPA under comparable treatment regimens.

Authors 10

1. Stefan Krämer corresponding Aachen Department of Nephrology and Clinical Immunology

   RWTH Aachen University · Universitätsklinikum Aachen

   Affiliation as printed

   Department of Nephrology and Clinical Immunology, RWTH Aachen University Hospital , Pauwelsstraße 30, Aachen 52074 ,

2. Kristian Vogt Aachen Department of Nephrology and Clinical Immunology

   RWTH Aachen University · Universitätsklinikum Aachen

   Affiliation as printed

   Department of Nephrology and Clinical Immunology, RWTH Aachen University Hospital , Pauwelsstraße 30, Aachen 52074 ,

3. Martin Busch

   Jena University Hospital · Friedrich Schiller University Jena

   Affiliation as printed

   Department of Internal Medicine III, University Hospital Jena, Friedrich-Schiller University , Jena ,

4. Tobias Schmitt

   Jena University Hospital · Friedrich Schiller University Jena

   Affiliation as printed

   Department of Internal Medicine III, University Hospital Jena, Friedrich-Schiller University , Jena ,

5. Raoul Bergner

   Klinikum Ludwigshafen

   Affiliation as printed

   Department of Internal Medicine A, Nephrology and Rheumatology, Municipal Hospital Ludwigshafen , Ludwigshafen ,

6. Sebastian Mosberger

   Klinikum Ludwigshafen

   Affiliation as printed

   Department of Internal Medicine A, Nephrology and Rheumatology, Municipal Hospital Ludwigshafen , Ludwigshafen ,

7. T. Neumann

   Kantonsspital St. Gallen

   Affiliation as printed

   Department of Rheumatology and Immunology, Cantonal Hospital St. Gallen , St. Gallen ,

8. Teresa Maria Schreibing Aachen Department of Nephrology and Clinical Immunology

   RWTH Aachen University · Universitätsklinikum Aachen

   Affiliation as printed

   Department of Nephrology and Clinical Immunology, RWTH Aachen University Hospital , Pauwelsstraße 30, Aachen 52074 ,

9. Fabian Schumbrink Aachen Department of Nephrology and Clinical Immunology

   RWTH Aachen University · Universitätsklinikum Aachen

   Affiliation as printed

   Department of Nephrology and Clinical Immunology, RWTH Aachen University Hospital , Pauwelsstraße 30, Aachen 52074 ,

10. Thomas Rauen Aachen Department of Nephrology and Clinical Immunology

    RWTH Aachen University · Universitätsklinikum Aachen

    Affiliation as printed

    Department of Nephrology and Clinical Immunology, RWTH Aachen University Hospital , Pauwelsstraße 30, Aachen 52074 ,