Abstract
INTRODUCTION: The aim of this study was to evaluate the relationship between modified primary efficacy renal response (PERR, mPERR) and modified complete renal response (CRR, mCRR) at 24 months postbiopsy and long-term kidney outcomes in childhood-onset lupus nephritis (LN, cLN). METHODS: We conducted a cohort study of biopsy-proven cLN diagnosed at the age of <18 years between 2001 and 2023, with prospective data collected from 2021 to 2025. We examined the relationship between modified versions of PERR (mPERR) and CRR (mCRR) at 24 months postbiopsy and survival free from advanced chronic kidney disease (CKD), including kidney failure (CKD 4-5D/T). RESULTS: One hundred seven Chinese children (93 female; median age at diagnosis: 13.7, interquartile range [IQR]: 11.0-16.6 years) were analyzed. Ninety-seven (91%) had proliferative LN. The median observation period was 12.0 (IQR: 6.4-17.8) years. At 24 months postbiopsy, 93 (87%) and 81 (76%) subjects were mPERR and mCRR responders, respectively. Kaplan-Meier analysis showed mPERR responders at 24 months had superior CKD 4-5D/T-free survival (responders: 100%, 98.8%, and 97.2%; nonresponders 92.9%, 78.6%, and 78.6% at 1, 5, and 10 years following 24 months postbiopsy; log-rank P = 0.013). Achieving mCRR trended toward better kidney survival. Multivariable analysis identified 24-months mPERR nonresponse (adjusted hazard: 4.39, 95% confidence interval CI: 1.04-18.4, P = 0.04) and baseline estimated glomerular filtration rate (eGFR) < 60 ml/min per 1.73 m(2) (adjusted hazard: 6.07, 95% confidence interval: 1.21-30.39, P = 0.03) as predictors of CKD 4-5D/T. Forty-four subjects (41%) experienced 89 kidney relapse episodes. Kaplan-Meier analysis showed that nonresponse by mPERR (log-rank P < 0.001) and mCRR (log-rank P = 0.03) at 24 months were associated with inferior relapse-free survival. CONCLUSION: mPERR at 24 months predicts long-term kidney survival in cLN. Achieving mPERR and mCRR shows significant benefits on lower risk of renal relapse.