Evaluating renal disease in pediatric‐onset anti‐neutrophil cytoplasmic antibody‐associated vasculitis: disease course, outcomes, and predictors of outcome

Objectives We aimed to study the disease course, outcomes, and predictors of outcome in pediatric‐onset anti‐neutrophil cytoplasmic antibody (ANCA)‐associated vasculitis (AAV) affecting the kidneys. Methods Patients eligible for this study had a diagnosis of granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), or ANCA positive pauci‐immune glomerulonephritis, were ≤ 18 years at diagnosis, had renal disease defined by biopsy or dialysis dependence, and had clinical data at diagnosis and either 12‐ or 24‐months. Ambispective data from the ARChiVE/PedVas Registry was used. The primary outcome was inactive renal disease (PVAS = 0 or 1) at 12‐months. Secondary outcomes included rates of improved renal function and damage within 24‐months. Renal function, defined by estimated glomerular filtration rate (eGFR), was categorized into KDIGO (Kidney Disease Improving Global Outcomes) stages at diagnosis and tested as a predictor of outcome using a proportional odds logistic regression model. Results 145 patients were included. 68% were female, 78% had GPA. At 12‐months, 83% of patients achieved inactive renal disease; however, 42% had evidence of permanent renal damage. Compared to patients with normal renal function at diagnosis, patients with moderate‐to‐severely reduced renal function, or kidney failure at diagnosis had an odds ratio of 8.62 ( p= 0.002, 95% CI: 2.31, 32.1) and 26.3 (p <0.001, 95% CI: 6.32, 109), respectively, for being in a worse KDIGO category at 12‐months. Conclusion The majority of pediatric‐AAV patients achieve inactive renal disease by 12‐months; however, almost half have evidence of damage. Renal function at diagnosis is a strong predictor of renal function at 12‐months. image