The value of the current histological scores and classifications of ANCA glomerulonephritis in predicting long-term outcome.

Background: Three different histological scores-histopathologic classification (Berden), Renal Risk Score (RRS) and the Mayo Clinic Chronicity Score (MCCS)-for anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (ANCA-GN) were compared to evaluate their association with patient and kidney prognosis of ANCA-GN.

Methods: Patients aged >18 years with at least 1 year of follow-up and biopsy-proven ANCA-GN entered this retrospective study. Renal biopsies were classified according to Berden's classification, RRS and MCCS. The first endpoint was end-stage kidney disease (ESKD), defined as chronic dialysis or estimated glomerular filtration rate <15 mL/min/1.73 m. The second endpoint was ESKD or death.

Results: Of 152 patients 84 were males, with median age of 63.8 years and followed for 46.9 (interquartile range 12.8-119) months, 59 (38.8%) reached the first endpoint and 20 died. The Kaplan-Meier curves showed that Berden and RRS were associated with first (Berden:  = .004, RRS:  < .001) and second (Berden:  = .001, RRS:  < .001) endpoint, MCCS with the first endpoint only when minimal + mild vs moderate + severe groups were compared ( = .017), and with the second endpoint ( < .001). Among the clinical/histological presentation features, arterial hypertension [odds ratio (OR) = 2.75, confidence interval (95% CI) 1.50-5.06;  = .0011], serum creatinine (OR = 1.17, 95% CI 1.09-1.25;  < .0001), and the percentage of normal glomeruli (OR = 0.97, 95% CI 0.96-0.99;  = .009) were the independent predictors of ESKD at multivariate analysis. When the three scores were included in multivariate analysis, RRS (OR = 2.21, 95% CI 1.15-4.24;  = .017) and MCCS (OR = 2.03, 95% CI 1.04-3.95;  = .037) remained predictive of ESKD, but Berden (OR = 1.17, 95% CI 0.62-2.22;  = .691) did not.

Conclusion: RRS and MCCS scores were independent predictors of kidney survival together with high serum creatinine and arterial hypertension at diagnosis, while Berden classification was not.