Epidemiology of Childhood-Onset Systemic Lupus Erythematosus: A Population-Based Study.

Objective: To characterize the incidence and prevalence of childhood-onset systemic lupus erythematosus (SLE), and to estimate the proportion of patients who are diagnosed with SLE during childhood.

Methods: A cohort of patients with incident childhood-onset SLE from 1976 to 2018 from an 8-county region in the US were identified based on comprehensive medical record review. All patients met the European Alliance of Associations for Rheumatology (EULAR)/American College of Rheumatology (ACR) classification criteria for SLE or the ACR SLE classification criteria from 1997 at or before age 18 years. Incidence rates were estimated using Poisson methods. We estimated the childhood-onset SLE point prevalence for January 1, 2015. Results were sex and age adjusted to the US 2000 population. Among all the SLE patients living in the 8-county region on January 1, 2015, the proportion of patients diagnosed at ≤18 years was estimated.

Results: A total of 13 children were diagnosed with childhood-onset SLE during the study period (using the EULAR/ACR definition; mean age at diagnosis 15.1 years, 85% female, 69% White). Childhood-onset SLE overall adjusted incidence rate was 0.7 (95% confidence interval [95% CI] 0.2-1.1) per 100,000 children. The incidence rate in girls was 1.2 (95% CI 0.5-1.9) per 100,000 children, while in boys it was 0.2 (95% CI 0.0-0.5) per 100,000. The adjusted prevalence of childhood-onset SLE was 1.1 (95% CI 0.0-3.1) per 100,000 children. The proportion of patients with SLE diagnosed as children was 9% (95% CI 6-13%).

Conclusion: In this population-based study, both the incidence and prevalence rates of childhood-onset SLE were ~1 per 100,000 children. One in 10 adults with SLE was diagnosed in childhood. More studies are needed to further characterize the epidemiology of childhood-onset SLE in minorities.