Kidney disease can predict 1-year outcomes in childhood ANCA-associated vasculitis
Key takeaways:
- Most children with ANCA-associated vasculitis had active kidney disease and impaired renal function at diagnosis.
- Those with normal or minimal kidney impairment had good chance of recovery.
Nearly all children with ANCA-associated vasculitis demonstrate active kidney disease at diagnosis, and their renal function status is strongly predictive of outcomes 1 year later, according to data published in Arthritis & Rheumatology.
“Children with ANCA vasculitis have high rates of kidney disease,” Kimberly A. Morishita, MD, MHSc, clinical assistant professor of pediatrics at the University of British Columbia, told Healio. “Adult studies and smaller studies in children have shown that kidney disease is often severe and associated with significant morbidity.”
To better understand disease course and outcomes specific to children with ANCA-associated vasculitis impacting the kidneys, and explore markers that might predict outcomes, Morishita and colleagues analyzed data from A Registry for Children with Vasculitis and the Pediatric Vasculitis Initiative. Their study included 145 children diagnosed ANCA-associated vasculitis and renal disease (mean age at diagnosis, 13.8 years; 68% girls), 78% of whom had granulomatosis with polyangiitis and 22% of whom had microscopic polyangiitis.
The researchers examined the rates of inactive kidney disease at 12 months and 24 months, assessed using the renal subcomponent of the pediatric vasculitis activity score. They also examined what factors at diagnosis could predict impaired renal function, assessed via estimated glomerular filtration rate and classified according to Kidney Disease Improving Global Outcomes (KDGIO) criteria.
According to the researchers, nearly all patients presented with active renal disease at diagnosis. However, among those with available data, 83% achieved inactive renal disease at 12 months, while 98% achieved it at 24 months.
Still, substantial numbers demonstrated at least some kidney damage, assessed using the pediatric vasculitis damage index, at 12 months (42%) and 24 months (35%).
Baseline kidney function varied widely, with 29% classified as “normal” under KDIGO, 23% showing moderately-to-severely reduced function, and 17% in kidney failure. The odds of kidney impairment at 12 months were significantly elevated among patients with “severely reduced” function (OR = 8.62; 95% CI, 2.31-32.1) or kidney failure (OR = 26.3; 95% CI, 6.32-109) at baseline vs. patients with no baseline kidney impairment.
“By following kidney function across time points, certain patterns emerged,” Morishita said. “Children with normal or minimally impaired kidney function at diagnosis tend to maintain good function over time. On the other hand, children who present with kidney failure have very little chance of recovery, even after receiving the most intense treatment regiments.
“For patients with less extreme presentations (eg, moderate kidney impairment), the outcome is less predictable,” she added. “Knowledge of certain patterns of kidney disease will help inform how we counsel patients and their families about what to expect when they are diagnosed with ANCA kidney vasculitis.”
Morishita called for further research aimed at identifying “other potential markers that can help to inform prognosis in all patients, not just the ones with really mild or really severe disease.”
“If we can predict from an early stage how a child’s disease will behave and how it will respond to treatment, then we can better tailor treatment,” Morishita said. “We can use aggressive treatments when warranted but avoid them — and their serious side effects — when they aren’t needed or aren’t going to help.”
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