Evaluation of Factors Influencing Outcomes in Pauci-Immune Crescentic Glomerulonephritis: Single Centre Experience of 51 Cases

INTRODUCTION: Pauci-immune crescentic glomerulonephritis (PICGN) is rare form of glomerulonephritis that frequently presents as rapidly progressive renal failure. Several prior studies have evaluated role of various factors influencing outcomes in patients with PICGN. The histopathological classification proposed by Berden a decade earlier described difference in the outcomes of patients in the focal, crescentic, mixed and sclerotic category with best prognosis for focal and worst for sclerotic group. The newly proposed renal risk score of Brix takes into account both the histopathological parameters (% of normal glomeruli, tubular atrophy and interstitial fibrosis) and clinical parameter (eGFR) which influences outcome. METHODS: Retrospective study was performed between 2014 to 2018. Biochemical parameters and ANCA details were recorded and renal histopathology slides were reviewed and classified according to Berden's histopathologic classes. All the cases were further characterized into three groups based on renal risk score (Brix et al). Univariate, multivariate analysis for risk factors predicting ESRD and Kaplan Meier Survival Analysis were done. RESULTS: In the present study, we found eGFR (P 0.024), % of normal glomeruli (P 0.023) and IFTA (P 0.001) as important factors influencing renal outcome in patients with PICGN. More than 60% patients achieved complete remission with low renal risk score as compared to patients with high renal risk score in which 80% patients developed ESRD or death at follow up. We also found significant difference in survival among various renal risk categories (Log-Rank P = 0.001) as compared to Berden's international histological classification (Log-Rank P = 0.037) on Kaplan –Meier survival analysis. CONCLUSION: PICGN is a significant cause of mortality and morbidity. Renal histological factors such as % normal glomeruli at time of biopsy, degree of IFTA and renal risk score play an important role in assessing prognosis in these patients.