Value of Repeat Renal Biopsy in Lupus Nephritis: Histological Transitions, Treatment Impact, and Predictors of Repeat Biopsy and Active Disease.

BACKGROUND: Repeat renal biopsy frequently reveals changes in the histological pattern in lupus nephritis (LN) which can guide alterations in therapeutic decisions. However, the choice of which patients should undergo such a repetition on clinical ground remains insufficiently defined. We sought to identify independent clinical predictors for repeat biopsy. PATIENTS AND METHODS: We retrospectively evaluated 370 patients with biopsy-proven LN. A clinically indicated second renal biopsy was performed in 122 patients (33%) due to acute renal flares, persistent disease activity, or suspected progression. LN classes were classified as non-proliferative (classes I, II, V, VI) or proliferative (classes III, IV, and mixed). Crude odds ratios and multivariable logistic regression models adjusting for baseline age, sex, and LN classification were utilized to identify independent predictors. The treatment regimens were consolidated into broad categories of clinical management subsets to evaluate changes in therapeutic pathways. RESULTS: The initial biopsies showed, 30.5% of patients had non-proliferative and 69.5% proliferative LN. Histological transformation occurred in 68% of the repeat biopsies. Mixed LN classes increased significantly in the second biopsy from 7.4% to 22.9% (p<0.05). Multivariable regression identified longer systemic lupus erythematosus (SLE) disease duration as the sole independent clinical predictor for undergoing a second biopsy (22.2 ± 4.96 vs. 17.2 ± 6.29 years; Adjusted OR = 1.15, 95% CI: 1.06-1.25), indicating that shorter SLE duration corresponds to clinical stability and conservative management without re-biopsy. Baseline proliferative LN independently predicted active disease on repeat biopsy (Adjusted OR = 2.42, 95% CI: 1.09-5.38). Repeat biopsy findings led to immediate therapeutic modification in 82.8% of patients, most commonly therapy intensification in those with active proliferative transformations. CONCLUSIONS: Repeat renal biopsy revealed high rates of histological transitions and directly guided alterations in, therapeutic adjustment. A longer SLE duration predicted the need for repeat renal biopsy, and a baseline proliferative LN strongly predicts active disease on re-biopsy. Although long-term survival benefits cannot be inferred from this retrospective cohort, repeat renal biopsy remains an indispensable tool for optimizing individualized immunosuppressive therapy.