Influence of ethnicity on childhood‐onset systemic lupus erythematosus: Results from a multiethnic multicenter Canadian cohort

OBJECTIVE: To determine the influence of ethnicity and sociodemographic factors on disease characteristics of the Canadian pediatric lupus population. METHODS: Childhood-onset systemic lupus erythematosus (SLE) patients at 4 pediatric centers in Halifax, Montreal, Toronto, and Vancouver were consecutively recruited. Sociodemographics and disease data were collected. Patients were categorized by their primary self-selected ethnicity, and exploratory cluster analyses were examined for disease expression by ethnicity. RESULTS: We enrolled 213 childhood-onset SLE patients, and ethnicity data were available for 206 patients: white (31%), Asian (30%), South Asian (15%), black (10%), Latino/Hispanic (4%), Aboriginal (4%), and Arab/Middle Eastern (3%). The frequency of clinical classification criteria (malar rash, arthritis, serositis, and renal disease) and autoantibodies significantly differed among ethnicities. Medications were prescribed equally across ethnicities: 76% were taking prednisone, 86% antimalarials, and 56% required additional immunosuppressants. Cluster analysis partitioned into 3 main groups: mild (n = 50), moderate (n = 82), and severe (n = 68) disease clusters. Only 20% of white patients were in the severe cluster compared to 51% of Asian and 41% of black patients (P = 0.03). However, disease activity indices and damage scores were similar across ethnicities. CONCLUSION: Canadian childhood-onset SLE patients reflect our multiethnic population, with differences in disease manifestations, autoantibody profiles, and severity of disease expression by ethnicity.