ANCA-associated vasculitis in Hispanic Americans: an unrecognized severity

This study aims to compare the severity and outcomes of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) between Hispanics and Caucasians living in the same geographical area. All patients diagnosed with AAV at two academic institutions in Chicago from January 2006 to December 2012 were retrospectively and prospectively identified. Disease activity was measured with the Birmingham Vasculitis Activity Score (BVAS), and disease damage was measured with the Vasculitis Damage Index (VDI). Student's t test and chi-square tests were employed; p ≤ 0.05 was considered significant. Seventy patients with AAV were identified; 15 patients were excluded. Fifty-five patients were included in the study: 23 Hispanics and 32 Caucasians, 35 patients with granulomatosis with polyangiitis (Wegener's), 12 with microscopic polyangiitis, 7 with eosinophilic granulomatosis with polyangiitis, and 1 with renal-limited vasculitis. Compared to Caucasians, Hispanics had a higher BVAS at presentation (16.3 ± 7.6 versus 10.7 ± 7.5, p = 0.006), a higher VDI at presentation (2.90 ± 1.50 versus 2.06 ± 1.30, p = 0.030), and a cumulative VDI (3.90 ± 1.70 versus 2.50 ± 1.90, p = 0.010). Renal involvement was more common among Hispanics (85 % of Hispanics versus 48 % of Caucasians, p = 0.01). Seventy percent of Hispanics had acute renal failure (mean creatinine = 3.37 ± 4.4 mg/dl) of whom seven (50 %) required dialysis, versus 25 % of Caucasians (mean creatinine = 1.78 ± 1.57 mg/dl, p = 0.03) and only two requiring dialysis. Compared to Caucasians, Hispanics with AAV present with more severe disease and higher damage indices. Larger studies are required to confirm these findings and delineate the respective roles of environment and genetics in the pathogenesis of the disease.