Kidney Prognosis in ANCA-associated Vasculitis: The ANCLA Risk Score From a Latin American Historical Cohort

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a leading cause of rapidly progressive glomerulonephritis and a major contributor to end-stage kidney disease (ESKD). Prognostic tools remain limited, particularly in Latin American populations.

We historically analyzed 164 adults with biopsy-proven pauci-immune necrotizing and/or crescentic glomerulonephritis consistent with AAV, diagnosed between 2011 and 2024 at a tertiary referral center in Colombia. Clinical and histopathologic variables obtained near the kidney biopsy (≤30 d) were analyzed using Cox proportional hazards models. The primary outcome was ESKD, defined as initiation of chronic dialysis or sustained estimated glomerular filtration rate (eGFR) <15 mL/min/1.73 m². Independent predictors were used to derive the ANCLA (ANCA in Latin America) Risk Score. Model performance was evaluated using the area under the ROC curve (AUC), Harrell C-index, and Kaplan-Meier analysis.

During a median follow-up of 12.9 months, 63 patients (38.4%) progressed to ESKD. Independent predictors included younger age, lower eGFR, higher 24-hour proteinuria, and a lower percentage of normal glomeruli. The ANCLA model demonstrated strong discrimination (AUC: 0.82, 95% CI: 0.79-0.85; C-index 0.72). Risk quartiles showed distinct kidney survival, with 2-year survival of ~95% in the lowest group versus <20% in the highest (log-rank p < 0.001). In comparative exploratory analyses, ANCLA outperformed the Berden classification and the Renal Risk Score within our cohort.

The ANCLA Risk Score integrates routine clinical and histopathologic data into a simple, accurate tool for predicting kidney outcomes in AAV, including ANCA-negative cases (17.1%). Its strong performance in a Latin American cohort supports its potential for early risk stratification and clinical decision-making. External and multicenter validation are warranted.