Repeat Kidney Biopsy in Lupus Nephritis: Diagnostic Yield and Clinical Utility in a Real-World Single-Centre Cohort

Background/Objectives: Repeat kidney biopsy in lupus nephritis is increasingly used to resolve discrepancies between clinical, serological and histological findings, but its diagnostic yield in real-world practice remains incompletely defined. This study aimed to describe the indications, safety, histological transitions, clinically relevant findings, treatment changes and clinical course of patients with lupus nephritis undergoing repeat native kidney biopsy. Methods: We conducted a retrospective single-centre study including adults with biopsy-proven lupus nephritis attended between 2003 and 2025 who underwent at least one repeat native kidney biopsy. Analyses were performed at patient level, comparing the index and last biopsy, and at episode level, evaluating consecutive biopsy transitions. Results: Nineteen patients and 45 native kidney biopsies were included. The most frequent indication for repeat biopsy was serological and/or proteinuric worsening. Comparing the index and last biopsy, histological or diagnostic change was observed in 14/19 patients (73.7%), including diagnoses not compatible with active lupus nephritis in 3/19 (15.8%). Sequential analysis identified 26 transitions; 17/26 (65.4%) showed lupus nephritis class change, 4/26 (15.4%) incident membranous component and 3/26 (11.5%) a diagnosis that was not compatible with active lupus nephritis. Two biopsy-related hematomas occurred and three patients required kidney replacement therapy during follow-up. Conclusions: In this real-world cohort, repeat kidney biopsy provided clinically relevant and potentially actionable diagnostic information, particularly through sequential analysis of consecutive biopsies.