Background/Purpose: Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) has been most extensively described and studied in non-African-American populations. The significance of and associations with ANCA in African-Americans, especially outside of AAV, has not been well characterized.

Methods: Retrospective chart review of patients self-identified as African-American with positive ANCA testing was performed. Records were reviewed in detail to classify patients as definite AAV using the revised Chapel Hill 2012 AAV criteria, probable AAV (in patients in whom biopsy evidence was absent but with a preponderance of clinical and serologic evidence to support the diagnosis), possible AAV (no biopsy evidence, compatible clinical/serologic picture, but less compelling evidence), and unlikely AAV. The presence of other autoimmune disorders, infectious disorders, and medications known to be associated with ANCA positivity were also documented.

Results: 77 African-American patients with ANCA were identified, of which 49 (63.6%) were female with a mean age of 57 at symptom onset. Of these patients, 21 had established AAV (27.3%), 3 had probable AAV (3.9%), 14 had possible AAV (18.2%) and 10 (13%) were deemed unlikely to have AAV. Eleven patients (14.3%) had drug-induced vasculitis, either from hydralazine or cocaine use. Sixteen patients (20.8%) had other autoimmune diseases, and of these, half were determined to have active vasculitis. Only 2 patients (2.6%) had vasculitis secondary to chronic viral infection (hepatitis). Patients most often were P-ANCA positive (51.9%), and often had other positive autoimmune serologies including antinuclear antibodies (42.9%) and rheumatoid factor (18.2%). Remarkably, 30 patients (38.9%) developed end-stage renal disease (ESRD). Considering other common comorbidities in this population potentially related to renal failure, diabetes mellitus (DM) was present in 20.7% of patients (mean duration=2 years, mean glycated hemoglobin=6.2) and hypertension (HTN) in 76.6% (mean duration 8 years, mean number of medications=1). Fourteen patients (18.1%) died, with a mean time to death of only 10 months from the time of their underlying diagnosis associated with ANCA.

Conclusion: ANCA are often detected in conditions other than AAV in African-American patients, and are frequently associated with other etiologies of vasculitis. Over one-third of African-American patients with ANCA developed ESRD, which given the data regarding HTN and DM in this population, seems unlikely to be wholly attributable to these comorbidities alone. Further study to explore the potential pathogenic role of ANCA in African-American patients, especially in regard to renal disease, is warranted.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/anti-neutrophil-cytoplasmic-antibodies-anca-in-african-american-patients-disease-associations-and-clinical-outcomes-in-an-urban-cohort/