Application of the ANCA Renal Risk Score in the United States: A Single-Center Experience

Abstract

Application of the ANCA Renal Risk Score in the United States: A Single-Center Experience To the Editor: Disease manifestations of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis are diverse and prediction of disease course remains challenging. This includes its kidney involvement, with wide variability in clinical and histologic presentation. Up to 64% to 85% of patients with ANCA-associated vasculitis develop a crescentic glomerulonephritis (GN) with a histologic spectrum from early fibrinoid necrosis to global sclerosis. Significant strides have been made in the diagnosis and treatment of ANCA-associated vasculitis. However, a significant proportion of patients progress to end-stage kidney disease (ESKD) and often experience treatment-related adverse effects, including infection. Disease prognostication in ANCA-associated vasculitis remains elusive and previous attempts of histopathologic classifications are not devoid of limitations. Although kidney biopsy has diagnostic and prognostic value in ANCA-associated GN, the predictive value is enhanced when histologic parameters are combined with clinical parameters. The recently developed ANCA renal risk score (ARRS) incorporates not only histologic features but also estimated glomerular filtration rate (eGFR) at the time of diagnosis to predict kidney survival. The ARRS was validated first in a cohort of 115 patients in Germany and then with similar results in England and Turkey. This risk score is now applied in a cohort of patients with ANCA-associated vasculitis for the first time in the United States to ascertain its validity.