The correlation between trajectories of serum C3 variability and clinical course in Pediatric-onset systemic lupus erythematosus.

Objective: The aim of this study is to investigate the usefulness which 2-year trajectories of C3 variability have in predicting clinical remission and systemic corticosteroids (SCS) use in pediatric patients with systemic lupus erythematosus (pSLE).

Methods: We recruited 189 confirmed pSLE patients from the electronic database of our hospital, all had undergone SCS treatment. The follow up period was 4.17-14.83 years. We used Group-Based Trajectory modeling to divide the patients into four different trajectory groups by their initial 2-year C3 variability. We divided the patients into groups A, B or C by their clinical course and SCS use. Statistical methods included Kruskal-Wallis and Chi-square tests and logic regression test.

Results: There were 4 separate trajectories. The distribution of groups A, B and C in these 4 trajectories showed a significant difference (p = 0.005). Initial C3 and C4 levels in these 4 revealed significant differences (p ≦ 0.001, p ≦ 0.016). When compared to other trajectories, trajectory1 showed a higher risk for persistent SCS use (p < 0.05). The distributions of severe clinical manifestations, including proteinuria, hematuria, CNS involvement and thrombocytopenia were different in these 4 trajectories (p = 0.003). Nevertheless, none of the above manifestations contributed to the risk of persistent SCS use.

Conclusions: We have found 4 distinct C3 trajectories in pSLE patients. Distributions of clinical outcome groups were different in these 4 trajectories. Patients with trajectory1 displayed a higher risk for persistent SCS use, thus an earlier institution of immunosuppressant(s) and biological agents can be considered for these children.