Background/Purpose: Protocolized and non-protocolized repeat renal biopsies are rarely performed in ANCA glomerulonephritis. Their role in predicting long term renal outcomes and aiding in clinical decisions have not been deeply analyzed. The aim of this study was to evaluate usefulness of renal re-biopsy in patients with ANCA glomerulonephritis in treatment decisions and the role of hematuria as a sign of active disease

Methods: We included retrospectively all patients with biopsy-proven ANCA glomerulonephritis: granulomatosis with polyangiitis (GPA), granulomatosis with polyangiitis and eosinophilia (GPAE), microscopic polyangiitis (PAM) and renal limited vasculitis (RLV) between January 2002 and May 2017. We analysed patient’s baseline characteristics, induction and maintenance treatments, renal response after induction and time to renal relapse/rebiopsy. Histology of re-biopsies was reviewed and correlation with clinical findings (hematuria) and first biopsy histology was analyzed. Histological classification was made according to 2010 classification criteria for ANCA glomerulonephritis (four categories: focal, crescentic, mixed and sclerotic). Data of physicians’ decisions after rebiopsy was collected

Results: 60 patients (77% females) were included. Of those, 15 (25%) underwent renal re-biopsy during the follow up based on clinical manifestations. Mean time until re-biopsy was 38.4 months (SD 20.4). In the re-biopsy group, 73% of patients had new onset hematuria vs. 7.5% in the no-rebiopsy group (p=). New onset or worsening proteinuria was present in 73% of patients in the re-biopsy group (40% and 33% respectably) vs. only 2.5% in the no-rebiopsy group. Decline in the GFR was present in 60% of patients in the re-biopsy group vs. 2.5% in the other. When analysing histological changes in the repeat biopsy we didn’t find a correlation between active lesions (crescents, necrosis etc.) and hematuria. All patients that underwent repeat biopsy were considered to be active but renal histology showed progression in terms of chronicity and rare active histological lesions (table 1). Despite this lower percentage of active lesions, in 67% of patients, physicians made a treatment change, initiating a new induction therapy regimen and achieving renal response in 85% of patients.

Conclusion: Renal histology in repeat biopsies did not showed active lesions justifying clinical renal manifestations that lead to re-biopsy. In spite of this, physicians made a change in treatments in the majority of cases after rebiopsy. Patients who presented with new onset hematuria, proteinuria and worsening in the GFR had a good response to this new induction treatment achieving renal laboratory remission in 85% of patients. Role of histological findings in rebiopsies has to be further analyzed.

TABLE 1. Comparison of histological classification in the first and second renal biopsy

*only patients who underwent a second biopsy

« Back to 2017 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/non-protocolized-re-biopsy-in-patients-with-anca-associated-glomerulonephritis-is-it-necessary/