Childhood‐onset systemic lupus erythematosus and immune thrombocytopenia: Prevalence and risk factors

Background There are few studies examining the prevalence and clinical risk factors for subsequent systemic lupus erythematosus (SLE) development after long‐term follow‐up in childhood immune thrombocytopenia (ITP). The aims of this study were to evaluate the prevalence and risk factors for subsequent SLE development in childhood ITP. Methods The medical records of childhood ITP patients aged under 15 years in a major tertiary care center in Southern Thailand were retrospectively reviewed. The Kaplan–Meier method was used to estimate the cumulative probability of subsequent SLE development after ITP. Logistic regression analysis was used to identify independent risk factors for SLE development. Results A total of 473 childhood ITP cases were included in the study. During a mean follow‐up time of 6.1 ± 6.7 years, the prevalence of subsequent SLE development was 2.96%. Older age at ITP diagnosis (odds ratio [OR]: 1.24, 95% CI: 1.07–1.45) and chronic ITP (OR: 24.67, 95% CI: 3.14–100.0) were independent risk factors. The cumulative probabilities of subsequently developing SLE at 5 and 10 years after diagnosis of ITP were 3.8% (95% CI: 1.4–6.2) and 6.5% (95% CI: 2.9‐9.8), respectively. Conclusion Older age at ITP diagnosis and chronic ITP were risk factors for subsequent SLE developed in childhood ITP.