Histopathologic and clinicopathologic classifications of antineutrophil cytoplasmic antibody-associated glomerulonephritis: a validation study in a Korean cohort

Abstract

Background: Antineutrophil cytoplasmic antibodies (ANCA)-associated glomerulonephritis (AAGN) is a common cause of rapidly progressive glomerulonephritis and requires prompt and proper immunosuppressive therapy to improve renal prognosis. This study aimed to evaluate the predictive value of two different classifications for renal outcomes in Korean AAGN patients. Methods: Ninety-two patients who were diagnosed with AAGN at two tertiary hospitals between 2004 and 2018 were retrospectively analyzed retrospectively. The histopathologic classification according to glomerular pathology and the clinicopathologic classification according to normal glomeruli ratio, degree of interstitial fibrosis/tubular atrophy, and baseline renal function were evaluated using the Cox proportional hazards model. Results: Forty-five patients (48.9%) progressed to end-stage kidney disease (ESKD) during the observation period. The mean age was 61.0 ± 15.3 years, and most patients had myeloperoxidase-ANCA (93.5%). In the histopathologic classification, the best renal survival occurred in the focal class, whereas the sclerotic class had the worst renal survival (sclerotic class vs. focal class; adjusted hazard ratio [aHR], 5.05; 95% confidence interval [CI], 1.32-19.31; p = 0.018). The mixed class had intermediate renal outcomes (mixed class vs. focal class; aHR, 4.23; 95% CI, 1.23-14.58; p = 0.022). In the clinicopathologic classification, the high-risk group had poor renal outcomes compared with the low-risk group (aHR, 6.56; 95% CI, 1.25-34.26; p = 0.026), but renal outcomes did not differ between the low-and medium-risk groups.

Evaluation of three scoring systems for predicting renal prognosis in antineutrophil cytoplasmic antibody-associated glomerulonephritis

“…The RRS has been validated as a good prognostic tool for renal disease in Japan, Korea, Mexico, and Spain [ 5 , 6 , 12 , 13 ]. In the present study, renal prognosis deteriorated sequentially in the low, medium, and high RRS groups, which is consistent with the findings of Brix et al The present study has similar background characteristics to studies in Japan and Korea [ 14 – 16 ], but is in contradiction with their study, which showed a similar prognosis for the medium RRS group and the low RRS group [ 5 , 6 ]. There are several possible reasons for this inconsistency.…”

“…The renal risk score (RRS) is based on three parameters-estimated glomerular filtration rate (eGFR), percentage of normal glomeruli, and rate of renal tubular atrophy and interstitial fibrosis (TA /IF)—which are classified into three groups according to severity. There is increasing evidence that RRS plays an important role in predicting renal prognosis in ANCA-associated glomerulonephritis (AAGN) [ 4 – 6 ]. Chen et al reported that Birmingham Vasculitis Activity Score (BVAS) was associated with poor renal prognosis in AAGN [ 7 ].…”

Renal histopathological indices for predicting the progression to end-stage kidney disease in patients with antineutrophil cytoplasmic antibody-associated vasculitis and glomerulonephritis: a single-centre study in Korea

“…They also demonstrated higher kidney survival rates in the order of focal, crescentic, mixed, and sclerotic classes (12). A recent study provided information on the predictive potential for kidney outcomes of both histopathological and clinicopathologic classi cations in Korean patients with AAV-GN (13). However, the study had three limitations.…”

“…* eGFR (* during follow-up(12,13). First, this may occur due to the heterogeneous nature of the focal class, which may include glomeruli with an underlying pathology that is not yet fully observable by light microscopy.…”

The predictive value of Berden's classification versus renal risk score for renal survival of Chinese patients with myeloperoxidase-anti-neutrophil cytoplasmic antibody-associated glomerulonephritis

“…Some studies compared the prognostic values of Berden's classification versus RRS for renal outcomes and revealed that RRS had better predictive ability than Berden's classification. However, these studies were limited to comparing discrimination ability and predicting overall survival (13)(14)(15). A more comprehensive comparison between Berden's classification and RRS are needed.…”