RESUMEN
OBJECTIVE: The aim of this study was to evaluate prognostic factors associated with advanced chronic kidney disease (ACKD) in a cohort of patients with ANCA-associated vasculitis and renal involvement. METHODS: Observational retrospective study. We included patients with biopsy-proven ANCA glomerulonephritis (GN) diagnosed between 2001 and 2016, with at least 1-year follow-up. Data were recorded at diagnosis, end of induction, after 12 months of treatment, and at the end of follow-up. We analysed clinical-analytical data and renal histopathology, as well as treatments, dialysis requirement, relapses and death. Univariate analysis was performed to identify factors associated with long-term ACKD (eGFR < 30 ml/min). Multivariate analysis using an alternative outcome (eGFR at the end of follow-up) was performed. Diagnostic accuracy for ACKD of each predictor variable was compared using AUC of ROC curves. RESULTS: Sixty patients were included: 17 GPA, 14 MPA, 5 EGPA, and 24 RLV. Forty-six patients were women (76.7%). Mean age at diagnosis was 67.8 years (SD 13.1), and median follow-up time was 4.2 years (IQR 2.2-6.8). At the end of follow-up, 12 patients (20.0%) had an eGFR < 30 ml/min. Univariate analysis showed a statistically significant association of ACKD with sclerotic class biopsy (OR 7.17, 95% CI 1.34-38.31), 12-month proteinuria (OR 5.16, 95% CI 1.16-22.87), and creatinine at diagnosis (OR 1.24, 95% CI 1.02-1.52), end of induction (OR 15.40, 95% CI 2.41-98.28), and after 12 months (OR 19.25, 95% CI 2.75-134.92). In the multivariate analysis, eGFR at baseline (< 0.001), after 6 months (< 0.001) and 12 months of treatment (< 0.001), remained statistically associated with eGFR at the end of follow-up. The best diagnostic accuracy in ROC curves was shown by serum creatinine at the end of induction treatment (AUC 0.93) and after 12 months (AUC 0.94). CONCLUSION: In this cohort of patients with ANCA GN, creatinine and eGFR at baseline and after 6 and 12 months of treatment were the best predictors of ACKD at the end of follow-up.