Background Lupus low disease activity state (LLDAS) is a treatment target for patients with SLE and is associated with decreased risk for severe flare and new damage. We investigated the utility of the achievement of LLDAS in children with lupus nephritis and whether attainment of LLDAS is associated with more favorable outcomes. Methods Data of children, diagnosed with biopsy-proven lupus nephritis between January 2012 and December 2020, were retrospectively analyzed. Results For patients who did not achieve LLDAS after initial treatment (first 6 months), presence of autoimmune hemolytic anemia (62% vs. 18%, p = 0.047), anti-Sm (85% vs. 18%, p = 0.003) and anti-dsDNA (77% vs. 27%, p = 0.038) antibodies, proliferative lupus nephritis (77% vs. 27%, p = 0.038), and hypertension (69% vs. 9%, p = 0.005) at onset were more frequently encountered. Also, a lower rate of complete kidney response (43% vs. 100%, p = 0.005) and a higher rate of hypertension (86% vs. 13%, p = 0.002) were observed in patients who did not achieve LLDAS-50, defined as being in LLDAS at least 50% of the observation time. Attainment of both LLDAS after initial treatment and LLDAS-50 were associated with lower rates of kidney flare (p = 0.001 and p = 0.002, respectively) and damage accrual (p = 0.007 and p = 0.02, respectively) through the observation period. Conclusions LLDAS is an attainable treatment target for children with lupus nephritis and associated with lower rates of kidney flare and damage. Presence of hematologic involvement, hypertension, and proliferative lupus nephritis at onset adversely influenced the early achievement of LLDAS.
