248. Refined Renal Risk Score for ANCA-associated glomerulonephritis

Background: Treatment related morbidity and mortality significantly impact outcome in ANCA associated glomerulonephritis (GN). The aim is to optimise kidney and patient survival by personalising medicine according to a reliable risk stratification. Methods: We conducted a multicentre, international retrospective study investigating patients with biopsy proven ANCA associated GN. We validated and refined the ANCA Renal Risk Score (ARRS) to optimise the outcome prediction for end stage kidney disease (ESKD) and the recovery from acute renal failure at presentation. Results: Six regional referral centres from the US, England, Turkey and Mexico, and the Irish national registry provided data on 766 patients with ANCA GN. Median age was 63 years (interquartile range 46 - 69), 56.4% of patients were male. 51.3% of patients were anti-myeloperoxidase positive, 42.6% anti-proteinase 3 positive and 6.1% ANCA negative. 17.6% initially required renal replacement therapy, and 57.7% of these patients recovered renal function. During a median follow up of 58 months, 26% of patients developed ESKD. The original risk score correlated with outcome; 12.5%, 24.4%, and 64.3% of patients developed ESKD in the low, moderate and high-risk groups, respectively (p=0.002). The risk score was modified by adjusting cut-offs according to regression tree analyses assigning risk points to create new risk groups. The refined score predicted renal recovery in patients presenting with dialysis dependent acute kidney injury (83.3%, 50%, 33.3%, p=0.02) as well as the development of ESKD during follow up (11.4%, 37%, 66.7%, p=0.0004). Conclusions: We developed and externally validated a reliable prediction tool enabling personalised medicine in ANCA associated GN. Adjusting the ARRS using real world data from around the globe optimised the risk stratification. Disclosures: DG is a consultant to ChemoCentryx and Aurinia Inc. NB and SRB received honoraria from Vifor. The other authors have no other disclosures or competing interests