#4006 ADDING 6-MONTH PARAMETERS FOR THE PREDICTION OF RENAL PROGNOSIS IN ANCA-ASSOCIATED GLOMERULONEPHRITIS

Abstract Background and Aims Antineutrophil-cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) with kidney involvement (AAV-GN) frequently evolves to end-stage kidney disease (ESKD) despite aggressive immunosuppressive treatment. Several risk scores have been used to assess renal prognosis. We aimed to determine whether kidney function and markers of AAV-GN activity after 6 months could improve the prediction of ESKD. Method This retrospective and observational study included adult patients with AAV-GN recruited from 6 French nephrology centers (including from the Maine-Anjou AAV registry). The primary outcome was kidney survival. Analyses were conducted in the whole population and in a sub-population that did not develop ESKD early in the course of the disease. Results 241 patients were included in the whole cohort, with a median follow-up of 59 months. At diagnosis, Berden classification and Renal Risk Score (RRS) were not found better than kidney function (eGFR) alone, at predicting ESKD (C-index = 0.70, 0.79, 0.82, respectively). At 6 months, 20 patients reached ESKD. In the sub-population of 221 patients, 6 months eGFR outperformed Berden classification and RRS (C-index = 0.88, 0.62, 0.69, respectively) to predict ESKD. RRS performed better when it was updated with the eGFR at 6 months instead of the baseline eGFR. While 6-months proteinuria was associated with ESKD and improved ESKD prediction, hematuria and serological remission did not. Conclusion This work suggests the interest of the reassessment of the renal prognosis 6 months after AAV-GN diagnosis. Kidney function at this time remains the most reliable for predicting renal outcome. To improve the long-term prediction of ESKD, there may be a place for repeated kidney biopsy following induction treatment, in order to obtain a precise evaluation of disease activity, discuss the immunosuppressive treatment strategy and improve prognosis scores.