Renal response at 2 years post biopsy to predict long-term renal survival in lupus nephritis: a retrospective analysis of the Hopkins Lupus Cohort

OBJECTIVE: This retrospective analysis evaluated the prognostic value of renal response status 2 years after biopsy-proven lupus nephritis (LN) for the prediction of long-term renal outcomes. METHODS: Eligible patients with SLE as per American College of Rheumatology or Systemic Lupus International Collaborating Clinics criteria and biopsy-proven class III, IV, V or mixed LN were identified from the Hopkins Lupus Cohort, and categorised into binary renal response categories (modified primary efficacy renal response (mPERR) or no mPERR at 2 years post biopsy). These categories were defined by a modified version of the Belimumab International Lupus Nephritis Study (BLISS-LN) protocol using urine protein:creatinine ratio (≤0.7 g/day) and estimated glomerular filtration rate (≥60 mL/min/1.73 m(2) or ≤20% below the baseline value) criteria. Long-term renal survival (defined as survival without end-stage renal disease (ESRD) or death) and chronic renal insufficiency-free survival were assessed in Kaplan–Meier plots with log-rank test and covariate-adjusted Cox proportional hazards models. RESULTS: Of the 173 eligible patients, 91.3% were female; the mean (SD) age at biopsy was 36.2 (11.8) years. At 2 years post biopsy, 114 (65.9%) patients achieved mPERR. These patients showed a lower risk of ESRD/death and chronic renal insufficiency in the follow-up period (HR (95% CI) 0.33 (0.13 to 0.87), p=0.0255; and HR (95% CI) 0.26 (0.14 to 0.47), p<0.0001, respectively). CONCLUSIONS: The 2-year post-biopsy renal response status, defined per 2019-updated BLISS-LN criteria, has prognostic value for long-term renal survival and lower risk of chronic renal insufficiency in patients with LN.