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Abstract: PO1940

Validation of the Renal Risk Score for ANCA-Associated Glomerulonephritis in a National Irish Cohort

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Scott, Jennifer, Trinity Health Kidney Centre, Dublin, Ireland
  • Brix, Silke R., The University of Manchester, Manchester, Manchester, United Kingdom
  • Slattery, Laura M., Trinity Health Kidney Centre, Dublin, Ireland
  • Clince, Michelle, Trinity Health Kidney Centre, Dublin, Ireland
  • Little, Mark Alan, Trinity Health Kidney Centre, Dublin, Ireland

Group or Team Name

  • Trinity Health Kidney Centre, Trinity College Dublin, Ireland
Background

Histopathological examination is currently the gold standard for diagnosis of ANCA-associated glomerulonephritis (AAV GN). However, the commonly used Berden score is inconsistent at predicting renal outcomes across different cohorts. Furthermore, treatment related morbidity remains a major problem. Brix et al. recently published a clinico-pathologic score to predict End-Stage Kidney Disease (ESKD), using 3 parameters to stratify patients into 3 risk groups. Parameters include: percentage normal glomeruli (N0 >25% = 0 points, N1 10 to 25% = 4, N2 <10% = 6), percentage tubular atrophy and interstitial fibrosis (T0 ≤25% = 0, T1 >25% = 2), and estimated glomerular filtration rate at the time of diagnosis (G0 >15 ml/min/1.73 m2 = 0, G1 ≤15 ml/min/1.73 m2 = 3). The ultimate aim is to utilise this to personalise treatment, enabling the optimal balance of toxic immunosuppression for every patient.

Methods

The Rare Kidney Disease (RKD) registry is an Irish national longitudinal, multi-centre, cohort study which includes 567 AAV patients, to date, diagnosed using the European Medicines Agency Algorithm (1990-2019). Patients with Granulomatosis with polyangiitis (GPA) or Microscopic polyangiitis (MPA), with biopsy proven AAV GN and positive PR3 or MPO serology were included in our validation of the renal risk score.

Results

248 patients, of whom 43 (17.3%) developed ESKD and 35 (14.1%) died, over a median follow up of 32 months (interquartile range, IQR 5 – 69.5 months), were identified. Outcome data and histopathologic details were available for 205 patients. Forty-five patients were in the lowest risk group (group 1) - two (4.4%) of which developed ESKD. Eight (8.6%) of the 93 patients in the middle risk group (group 2) reached ESKD. Sixty-seven patients were in the highest risk group (group 3) and 28 (41.8%) of them required permanent renal replacement therapy. Kaplan Meier survival analysis demonstrated a difference in renal outcome between the 3 risk groups (p < 0.0001).

Conclusion

The proposed renal risk score accurately predicts ESKD in patients with AAV GN, in our national Irish cohort. The next step is to further refine the predictive cut-off values for the 3 clinico-pathologic parameters using a regression tree analysis.