Predictive Value Of Renal Risk Score And Chronicity Score In Predicting Renal Outcome In Anca Associated Glomerulonephritis

Abstract Background and Aims Renal Risk Score (RRS) and Chronicity Score (CS) are both newly proposed tools to predict End stage renal disease (ESRD) which could be applicable in Antineutrophil cytoplasmic antibody (ANCA) associated glomerulonephritis (AGN) patients. Their predictive value has not been fully studied and compared. Method Patients with newly biopsy-proven AGN at Department of Nephrology, Ruijin Hospital were retrospectively studied. Patients were evaluated with RRS and CS for clinical factors, pathological lesions and outcome. Their predictive value of renal survival was also compared with 2010 histological classification. Results There were 252 AGN patients enrolled in current study, including 212 MPA, 12 GPA, 4 EGPA and 24 renal limited vasculitis (RLV). In current study, the median serum creatinine of patients at diagnosis was 245.5 μmol/L (IQR 128-487.5 μmol/L) and median eGFR was 20.3 ml/min (IQR 9-45.3 ml/min). Fifty (19.8%) patients required dialysis at disease onset. The median RRS score at diagnosis was 6 (IQR 0-9) and CS score was 4 (IQR 3-7). During up to 217 months of follow-up (mean 63.9 months), 71(28.2%) patients progressed to end stage renal disease (ESRD) and required renal replacement therapy. Significant differences were found regarding dialysis dependency within RRS and CS groups (p<0.001 and p<0.01 respectively). The C statistic of the predictive models was 0.828 (95% CI, 0.775-0.880) for developing ESRD required renal replacement therapy. The addition of RRS or CS scoring scheme to the model significantly improved discrimination. Compared with the 2010 histopathological classification, RRS and CS both showed adequate and similar discrimination, but significantly greater discrimination than 2010 histopathological classification. Conclusion Among AGN patients, RRS and CS achieved similar discrimination, but the discrimination of RRS was superior.