Clinical correlates and predictors of thrombocytopenia in childhood-onset systemic lupus erythematosus: a retrospective cohort study.

objectivesThis study sought to evaluate the clinical implications of thrombocytopenia in pediatric patients diagnosed with systemic lupus erythematosus (SLE) and to explore its relationship with various disease features. Furthermore, the research aimed to identify risk factors that affect the occurrence of SLE-associated thrombocytopenia.

methodsA single-center retrospective study was conducted involving 236 pediatric patients diagnosed with SLE at Children's Hospital of Fudan University from January 2020 and December 2025. Clinical information and laboratory parameters, such as complement levels, autoantibody profiles, and platelet counts, were systematically collected. Participants were divided into two groups and those without, based on their platelet counts at the time they were diagnosed with SLE. The presence of thrombocytopenia was determined at diagnosis, and further subgroup analyses were carried out based on the severity of the condition. All statistical analyses, such as logistic regression and one-way ANOVA, were conducted using SPSS version 26.0.

resultsThrombocytopenia was observed in 19.5% (46 out of 236) of the patients. In comparison to the cohort without thrombocytopenia, the thrombocytopenia group demonstrated significantly increased incidences of leukopenia, leukocyte reduction, and positivity for antiphospholipid antibody IgM, anti-β2-glycoprotein-1 antibody, and lupus anticoagulant (P < 0.05). Furthermore, severe thrombocytopenia (defined as a platelet count below 50 × 10⁹/L) was correlated with a markedly higher prevalence of lupus anticoagulant positivity relative to the mild-to-moderate thrombocytopenia subgroup. Logistic regression analysis revealed that leukopenia, elevated erythrocyte sedimentation rate (ESR), positivity for Anti-β2 glycoprotein 1 antibodies, high lupus anticoagulant, and neuropsychiatric manifestations were significantly associated with the presence of thrombocytopenia.

conclusionThrombocytopenia frequently occurs in pediatric patients with SLE and demonstrates a significant correlation with leukopenia, the presence of antiphospholipid antibodies, and involvement of major organs. Additionally, further multicenter prospective investigations are necessary to clarify the contribution of platelets to the pathogenesis of SLE. In clinical practice, when thrombocytopenia is identified in pediatric SLE patients, thorough evaluation for antiphospholipid antibodies and neuropsychiatric systemic lupus erythematosus (NPSLE) is warranted.