Comparison of renal remission and relapse‐free rate in initial‐ and delayed‐onset lupus nephritis

INTRODUCTION: Lupus nephritis (LN) is a major manifestation of systemic lupus erythematosus (SLE) which contributes to significant morbidity and mortality. It is unclear whether the timing of LN onset influences renal outcome. This study aimed to investigate differences in clinical features—particularly the relapse‐free rate—in remission duration from induction therapies for LN and the onset timing of LN after the development of SLE. METHODS: We enrolled 66 LN patients from January 2004 to March 2020. We collected the following: demographic data, laboratory data, renal histology data, and LN induction therapy data. Renal remission and relapse‐free rates were calculated for each group. RESULTS: Patients were first divided into early remission group (achieved renal remission in <12 months [n = 44]) and others (n = 22). There were no significant differences in clinical data, treatments, and relapse‐free rate of LN. Patients were then divided into initial‐onset LN (<12 months after development of SLE [n = 49]) and delayed‐onset LN (≥12 months after development of SLE [n = 17]). Kaplan–Meier analysis showed that the relapse‐free rate was significantly higher in all patients with initial‐onset LN than those with delayed‐onset LN (P = .0094). CONCLUSION: The relapse‐free rate was significantly higher in the initial‐onset LN group than the delayed‐onset LN group of patients with LN of various histopathological backgrounds. These data suggest that delayed‐onset LN is a risk factor for the relapse of LN.