Researchers have found a link between age of diagnosis and various clinical characteristics and outcomes in patients with antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV).
The findings, presented at the annual meeting of the American College of Rheumatology, may have implications for research and treatment, especially in children.
AAV is a group of conditions characterized by the development of autoantibodies to the neutrophil proteins proteinase 3 (PR3-ANCA) or myeloperoxidase (MPO-ANCA).
The rare autoimmune condition can cause systemic inflammation and damage, sometimes permanent, to small- and medium-sized arteries. Clinical presentations vary and can include several organs, including skin, stomach, intestines, lung, and kidney, as well as airways in ear, nose, and throat.
Data limited on child vs. adult characteristics
AAV can be diagnosed in any decade of life, but clinical characteristics and outcomes often differ between children and adults, and data are limited. Studies often exclude children.
Dr. Jessica Bloom
Lead author Jessica Bloom, MD, MSCS, a pediatric rheumatologist and assistant professor of pediatrics at Children’s Hospital Colorado, Aurora, and colleagues performed an analysis of patients with granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) who were enrolled in the Vasculitis Clinical Research Consortium Longitudinal Studies from 2013 to 2021.
Patients with eosinophilic GPA (EGPA) were analyzed separately. Children and young adults with EGPA were combined because of the small sample size (n = 87).
The groups were sorted by the age they were diagnosed: under 18 years old, 18-40, 40-65, and older than 65.
More than 1,000 patients included
Dr. Bloom’s team analyzed data from 1,020 patients: 61 diagnosed as children, 240 as young adults, 560 as middle-aged adults, and 159 diagnosed as older adults. At all ages, about nine out of 10 patients were White.
They found 852 (84%) had GPA and 165 (16%) had MPA. The analysis also showed 893 (92%) of patients with ANCA results were ANCA positive: 637 (65%) with PR3-ANCA, 247 (25%) with MPO-ANCA, and 9 (1%) with both.
Differences between age groups included:
- Children experienced more subglottic stenosis and alveolar hemorrhage than adults with the condition.
- About half of patients diagnosed in childhood received both cyclophosphamide and rituximab. That rate decreased with increasing age of diagnosis to as low as 14% for those diagnosed in older adulthood.
- More females than males in all age groups were diagnosed with AAV, but the difference was most pronounced when diagnosed in childhood, and female predominance declined as age increased.
- Older adults experienced more neurologic disease and less musculoskeletal and sinus involvement.
Additionally, for those diagnosed after age 65, after adjusting for disease length and whether they were taking cyclophosphamide and/or rituximab, the Vasculitis Damage Index (VDI) and ANCA Vasculitis Index of Damage (AVID) scores were higher than for those diagnosed in childhood.
“However, these differences are no longer significant when medication toxicity and comorbidity-related items are excluded. Thus, differences in the VDI and AVID scores are driven by non–disease-specific damage,” Dr. Bloom said.
Bringing children into the clinical discussion
Dr. Bloom said in an interview that
For example, the findings that children have more subglottic stenosis and alveolar hemorrhage than adults “may warrant more aggressive therapy,” she said. Children also have different growth and psychosocial risk factors during their disease course and may live longer with the disease than those in older age groups.
“Our study helps to point out these differences and bring children into the discussion,” Dr. Bloom said. “It also recognizes that damage scores used in studies and care may not adequately assess disease across the lifespan, as they are largely influenced by items not specific to the disease but rather medication toxicity and comorbidities, such as osteoporosis, cataracts, and malignancy.”
Dr. Robert F. Spiera
Robert Spiera, MD, director of the Scleroderma, Vasculitis, and Myositis Center at Hospital for Special Surgery, New York, said in an interview that the work highlights interesting information about the fact that disease features are skewed differently in children – “in particular the higher likelihood of upper airway [subglottic] disease, and potentially severe lower airway disease [alveolar hemorrhage].”
However, from a practical standpoint, Dr. Spiera said, “I am not sure that this will change our clinical approach to different patients, but the differences in disease features and even the sex differences in terms of who are afflicted with GPA [more often children and more likely to be female] may offer insights into disease pathogenesis.”
Dr. Bloom received funding from the Vasculitis Clinical Research Consortium and Vasculitis Foundation to conduct this work as a VCRC-VF fellow. Several coauthors reported various conflicts of interest with pharmaceutical companies. Dr. Spiera declared no relevant financial relationships.
A version of this article first appeared on Medscape.com.