European ancestry decreases the risk of early onset,severe lupus nephritis in a single center,multiethnic pediatric lupus inception cohort

Abstract

Purpose: To determine whether pediatric SLE patients without European ancestry are at higher risk for development of severe lupus nephritis (ISN/RPS class III, IV or V). Methods: Ninety-eight of 101 patients with pediatric SLE (age <18 years at diagnosis) were enrolled. Race/ethnicity of four grandparents, socioeconomic status (SES) and language proficiency were collected. The primary outcome was time to development of severe lupus nephritis. Results: Based on patient report of four grandparent ancestry, 29% had at least one grandparent of European ancestry (14% had all four grandparents of European ancestry). Patients without European ancestry were 46% Hispanic, 47% Asian, and 3% African American. In the entire 98 patient cohort, 12% had ≥3 different ancestries. Patients without European ancestry had significantly lower SES levels and English proficiency. There was no significant difference between patients with or without European ancestry in duration of SLE, age of onset, and lag time between symptoms and diagnosis. Patients with at least one grandparent of European ancestry had a decreased risk of developing severe lupus nephritis, which remained significant after controlling for age, gender, SES and English proficiency (hazard ratio 0.4, 95% confidence interval 0.2–0.9). Conclusion: This study demonstrates that presence of at least one grandparent of European ancestry decreases the risk of severe lupus nephritis, a finding that is not explained by measurable socioeconomic differences and language barriers.