Abstract / Summary
Abstract Objective : To investigate whether disease status at belimumab (BLM) initiation was associated with clinical outcomes in children with childhood-onset lupus nephritis (cLN). Methods : This single-center retrospective cohort study included children and adolescents with active cLN treated with intravenous BLM plus standard therapy at the Affiliated Hospital of Qingdao University between January 2020 and April 2026. Patients were classified into a newly diagnosed group (BLM initiation within 12 weeks after cLN diagnosis) or a relapsed group (BLM initiation within 12 weeks after LN relapse following renal remission). The primary outcomes were complete renal response (CRR) and partial renal response (PRR). Secondary outcomes included lupus low disease activity state (LLDAS), DORIS remission, disease activity, glucocorticoid dose reduction, and safety. Results : Thirty-six patients were included (25 newly diagnosed and 11 relapsed). At 12 months, CRR was achieved more frequently in the newly diagnosed group than in the relapsed group [94.7% (18/19) vs. 55.6% (5/9), P=0.026], as was LLDAS attainment [73.7% (14/19) vs. 22.2% (2/9), P=0.017]. Age-adjusted Cox models showed higher hazards of achieving LLDAS (HR=4.224, 95% CI 1.240–14.392, P=0.021) and DORIS remission (HR=4.552, 95% CI 1.265–16.379, P=0.020) in newly diagnosed patients. Disease activity, proteinuria, complement levels, and glucocorticoid doses improved in both groups, with greater improvement and faster steroid reduction in the newly diagnosed group. Conclusion : Among children with cLN treated with BLM-containing regimens, disease status at treatment initiation was associated with subsequent treatment trajectories. Patients receiving BLM during the newly diagnosed phase demonstrated more favorable achievement of renal response and treatment targets.