Risk of end-stage renal disease in patients with early-onset lupus nephritis: A population-based cohort study.

OBJECTIVE:To compare the risk of end-stage renal disease (ESRD) between patients with early-onset lupus nephritis (EOLN) and those with delayed-onset LN (DOLN). METHODS:This retrospective study of incident cases of systemic lupus erythematosus (SLE) used nationwide Korean claims databases and data from 2008 through 2018. We divided LN patients into two groups: the EOLN group (with LN onset within 12 months of SLE diagnoses) and the DOLN group (with LN onset later than 12 months after SLE diagnoses). Patients were observed from the date of LN diagnosis to the development of ESRD, death, or the last follow-up. Cox proportional hazards modeling was used to predict hazard ratios (HRs) for progression to ESRD with death as a competing risk. RESULTS:We identified 3779 incident SLE patients who developed LN during follow-up: 60 % (n = 2281) had EOLN, and 40 % (n = 1489) had DOLN. Sixty-nine patients with EOLN (3.0 %) and 29 patients with DOLN (1.9 %) progressed to ESRD. After adjusting for confounders, the ESRD risk associated with EOLN was comparable to the risk associated with DOLN (HR 1.10, 95 % confidence interval [CI] 0.57 to 2.11). In the subgroup of patients on aggressive immunosuppressive therapy (670 with EOLN and 179 with DOLN), the ESRD risk was higher in the DOLN group (HR 2.6, 95 % CI 1.11 to 6.10). CONCLUSION:The risk of ESRD was comparable between patients with EOLN and DOLN. However, among patients on aggressive immunosuppressive therapy, compared with EOLN, DOLN was associated with a higher risk of progression to ESRD.