# Reduction in Renal Relapse and Preservation of Long‐Term Kidney Function After Lupus Low Disease Activity in Patients With Lupus Nephritis

## TL;DR

Achieving low disease activity in lupus nephritis is linked to fewer relapses and better kidney function over time.

## Contribution

Demonstrates that LLDAS is an effective treatment target in LN, comparable to other renal response measures.

## Key findings

- LLDAS attainment at 12 months was associated with reduced LN relapse risk (HR 0.38).
- Combined CRR/PRR and LLDAS provided the best relapse-free survival (P < 0.001).
- LLDAS predicted renal function preservation with ROC AUC of 0.71.

## Abstract

Lupus low disease activity state (LLDAS) is a validated treatment target in systemic lupus erythematosus (SLE), but limited studies have explored the role of LLDAS in lupus nephritis (LN). This study aims to investigate the frequency and predictors of LLDAS attainment and its benefit on LN relapse and renal function preservation in patients with LN.

Patients with LN during 2010 to 2020 in Queen Mary Hospital and Pamela Youde Nethersole Eastern Hospital were included in the discovery cohort and validation cohort, respectively. Complete renal response (CRR), partial renal response (PRR), LLDAS, and Definition Of Remission In SLE (DORIS) remission were assessed at 12 months. Regression analysis was performed to identify risk factors of LN relapse. Receiver operating characteristic (ROC) curves were used to evaluate target attainment and long‐term kidney function.

A total of 245 patients with LN (discovery cohort n = 143 and validation cohort n = 102) were included. At 12 months, 57 of 143 (40%), 14 of 143 (10%), 70 of 143 (49%), and 15 of 143 (10%) patients achieved CRR, PRR, LLDAS, and DORIS remission, respectively. Attainment of both CRR/PRR and LLDAS at 12 months was associated with best relapse‐free survival (P < 0.001). Multivariate analysis showed independent association of CRR/PRR and LLDAS with LN relapse risk reduction (CRR/PRR: hazard ratio [HR] 0.31, P = 0.007; LLDAS: HR 0.38, P = 0.029). LLDAS attainment predicts renal function preservation with satisfactory performance in both the discovery and validation cohorts (area under the curve of the ROC 0.71).

LLDAS is an attainable target in LN comparable to CRR/PRR. Attainment of both targets is associated with additional benefits on relapse risk reduction. Early LLDAS attainment is associated with renal function preservation.