From a myth to a menace: Increased disease severity and poor outcomes in an urban cohort of african-american patients with ANCA-associated vasculitis
Arthritis and Rheumatology
Background/Purpose: Anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) is a systemic inflammatory disorder frequently associated with significant disability and morbidity, which may lead to end-stage renal disease (ESRD) or death. The purpose of our study was to examine disease characteristics and outcomes in an urban African-American (AA) cohort with AAV and compare them with a matched Caucasian (CA) cohort with AAV. Methods: A detailed electronic chart review of patients with positive anti-neutrophil cytoplasmic antibody testing was performed to identify patients with AAV using the 2012 Revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides. Patients with isolated renal disease were included if they demonstrated biopsy evidence of necrotizing pauci-immune glomerulonephritis with P-ANCA/MPO or C-ANCA/PR-3 positivity at the time of diagnosis. African-American AAV patients were matched 1:2 to CA patients with AAV by gender and age within 5 years. Results: 21 AA patients with AAV were identified, of which fourteen (66.7%) were female, with a mean age at diagnosis of 61 years. Microscopic polyangiitis occurred more commonly in AA patients than CA patients (38% vs. 14%), while granulomatosis with polyangiitis was more common in CA patients (76% vs. 47%). AA patients had more severe disease at the time of diagnosis, with increased need on admission for ICU care (50% vs. 23%, p=0.04), mechanical ventilation (40% vs. 10%, p=0.007), hemodialysis (52% vs. 19% p=0.007), with lower hemoglobin (mean 7.0 vs. 10.0, p=0.001), and higher serum creatinine (mean 6.1 vs. 2.7, p=0.001). Although the likelihood of receiving high dose pulse steroid therapy at diagnosis was not significantly different between groups, the mean dose of prednisone initiated at disease diagnosis in AA patients was significantly lower (143 mg vs. 455 mg, p=0.004), while the concomitant use of steroid-sparing immunosuppressive agents for induction therapy did not differ significantly between groups. There was a significant increase in the incidence of ESRD in AA patients when compared to CA patients (62% vs. 19%, p=0.001) without significant differences in the prevalence or severity of hypertension and diabetes at the time of diagnosis between groups. Death occurred in 33% of the AA patients and 21% of CA patients during follow up. Conclusion: In an urban cohort, AA patients with AAV were more likely to present with severe disease requiring ICU care, mechanical ventilation, and hemodialysis compared to Caucasian patients with AAV. Despite similar rates and severity of diabetes and hypertension in these populations, African-American patients were significantly more likely to develop ESRD. There are many factors that could influence these outcomes, including other comorbid conditions, genetics, differences in treatment and response to immunosuppressive therapies, environmental factors, and limited access to care because of socioeconomic factors. Further study is needed to better understand factors that influence AAV severity and course in this population in order to improve long-term outcomes and survival.