Lower-dose glucocorticoid therapy achieves comparable outcomes in Japanese patients with lupus nephritis

Objective: To evaluate the effectiveness of a lower initial glucocorticoid (GC) dose (0.4–0.6 mg/kg/day) compared to the conventional dose (0.8–1.2 mg/kg/day) in achieving complete renal response (CRR) at 12 months in Japanese patients with proliferative lupus nephritis (LN). Methods: This multicentre, retrospective observational study analyzed data from 344 Japanese patients diagnosed with LN (class III or IV ± V) via renal biopsy. Patients were divided into two groups based on their initial dose of GC. 1:1 propensity score matching (PSM) based on key baseline variables, 23 patients were included in each group. The primary endpoint was CRR at 12 months, defined according to the BLISS-LN trial criteria. A non-inferiority margin of −10% was prespecified. Results: After PSM, the CRR rate at 12 months was 87.0% in the low-dose group and 73.9% in the conventional-dose group (risk difference: 13.1%; 95% confidence interval [CI]: −9.4% to 35.6%), confirming statistical non-inferiority. While GC doses differed significantly during the initial 3 months, they became comparable between the groups after 6 months. Conclusion: A reduced initial GC dose of 0.4–0.6 mg/kg/day achieved renal outcomes comparable to conventional dosing in Japanese patients with LN. Given the risks of GC toxicity, these findings may support the potential for lower-dose GC strategies in LN treatment.