Background Juvenile systemic lupus erythematosus (jSLE) has more severe and aggressive clinical features than adult onset SLE. We investigated the risk factors related with long-term outcome among initial parameters at diagnosis.

Methods The study was designed for patients initially diagnosed with jSLE below 18 years old between January 2009 and December 2021. We excluded patients with previous diagnosis, transferred from another hospitals, clinical findings related with infection or post-transplantation, and underlying diseases. We reviewed retrospectively electronic medical records for initial laboratory data, and clinical manifestations including SLE disease activity index-2K (SLDAI-2k). We analyzed parameters associated with survival and events including flare, complications, and new organ involvement.

Results Total 109 patients were enrolled in this study. The mean age was 14.4 ± 2.3 years old, and the female to male ratio 7.4:1. Twenty-eight patients (25.7%) were diagnosed at pre-pubertal period. The overall survival rate was 92.9% (median: 5 years, range: 0 ~ 13 years). The causes of death were intractable macrophage activation syndrome, disease related state, and sepsis. The related factors for survival were initial C-reactive protein (CRP, P =0.017, HR: 2.396, 95% CI: 1.165 ~4.926) in multi-variate analysis, although there were associated with CRP, SLEDAI, and false positivity for syphilis (P < 0.05) in univariate analysis. The event free survival was 10.4% and related with SLEDAI, anti-smith antibody, false positivity for syphilis, and ANCA (P<0.05) in univariate analysis. In multivariate analysis, factors associated with event were SLEDAI-2K (P=0.035, HR: 2.82, 95% CI: 1.078 ~7.375), anti-Smith antibody (P=0.019, HR: 3.262, 95% CI: 1.218 ~ 8.741).

Conclusions These results suggested that initial SLEDAI and markers for immune response were related with survival and events during follow-up. We have to concern disease activity and laboratory parameters for long-term outcome in jSLE.