Background/Purpose:

ANCA-associated vasculitis, once a disease thought to predominate in Caucasians, is now increasingly recognized in diverse ethnic populations. However, there has been little systematic analysis of ANCA-associated vasculitis among minorities in the United States, particularly among Hispanics. We have observed anecdotally that Hispanics appeared to present with systemic disease and severe renal involvement. Here, we describe the clinical severity and disease outcome in a group of Hispanic patients with ANCA-associated vasculitides, and we test the hypothesis that Hispanics have more severe disease relative to an age- and gender-matched Caucasian population living in the same geographical area.

Methods:

We identified 21 Hispanic and 25 Caucasian patients treated for ANCA-associated vasculitis at Stroger Hospital of Cook County and Rush University Medical Center in Chicago, IL from January 2006 to December 2011.  Ethnicity was determined by self-report. The definition and diagnosis of Granulomatosis with Polyangiitis (Wegener’s; GPA), Microscopic Polyangiitis (MPA), and Churg-Strauss Syndrome (CSS) followed the American College of Rheumatology criteria and the 1992 Chapel Hill Consensus Conference criteria. Patient demographics, laboratory data, Birmingham Vasculitis Activity Score (BVAS), and Vasculitis Damage Index (VDI) were analyzed. The presence of renal involvement was defined by: elevated serum creatinine, hematuria >10RBC/hpf, RBC casts, and/or proteinuria> 1+.  Student’s t-test and chi-square tests were employed, p<=0.05 was considered significant.

Results:

Of the 46 patients, 27 had GPA, 11 had MPA, 7 had CSS, and 1 renal-limited vasculitis. There was no difference between Hispanics and Caucasians in the median age at diagnosis (49.5 years in Hispanics and 50.3 years in Caucasians, p=0.36), time to diagnosis (263 days in Hispanics and 288 days in Caucasians, p=0.72), nor in the gender distribution (47.6% females among Hispanics versus 64% among Caucasians, p=0.37). As opposed to Caucasians, Hispanics had a higher mean BVAS at presentation (16.75 ± 7.7 versus 12.4 ± 6.7, p=0.03), a higher mean VDI at presentation (2.9 ± 1.5 versus 1.9 ± 1.2, p=0.03) and a cumulative mean VDI (3.9 ± 1.7 versus 2.5 ± 1.9, p=0.01) in Hispanics versus Caucasians respectively. In addition, there was a trend towards higher prevalence of renal involvement in Hispanics (89% of Hispanics vs. 56% of Caucasians, p=0.06). Seventy percent of Hispanics had acute renal failure (Mean highest creatinine= 4.01 ± 3.01 mg/dl) of whom half required dialysis, versus 29% of Caucasians (Mean highest creatinine= 1.98 ± 1.67 mg/dl, p=0.05) and only two patients requiring dialysis. Two Hispanic patients died shortly after presentation. There were no deaths among Caucasians.

Conclusion:

In contrast to Caucasians, who tended to have a limited form of vasculitis at presentation, Hispanics with ANCA-associated vasculitis presented with more systemic and severe disease with higher damage indices. Whether these differences are due to genetic, socio-economic, or healthcare access disparities is yet to be studied. Early detection and intervention in these patients may alter the course of the disease and reduce morbidity and mortality.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/anca-associated-vasculitis-in-hispanic-americans-an-unrecognized-severity/