Granulomatosis with polyangiitis according to geographic origin and ethnicity: clinical-biological presentation and outcome in a French population.

Abstract

Granulomatosis with polyangiitis (GPA) mainly affects white Europeans, but rarely GPA may also affect non-Europeans. This study aimed to describe GPA clinical-biological presentation and outcome in black sub-Saharan Africans and Afro-Caribbeans and in North Africans. Among 914 GPA patients included in the French Vasculitis Study Group database, geographic origin and ethnicity were known for 760. Clinical-biological presentations and outcomes of white Europeans vs black sub-Saharans and Afro-Caribbeans and vs North Africans were analysed. Among the 760 patients, 689 (91%) were white Europeans, 33 (4.3%) were North Africans and 22 (2.9%) were sub-Saharans (n = 8) or Afro-Caribbeans (French West Indies, n = 14). Black sub-Saharans and Afro-Caribbeans, compared with white Europeans, were significantly younger at GPA diagnosis (P = 0.003), had more frequent central nervous system involvement (P = 0.02), subglottic stenosis (P = 0.002) and pachymeningitis (P = 0.009), and tended to have more frequent chondritis and retroorbital tumour. Median serum creatinine levels and Birmingham Vasculitis Activity Score were significantly lower in sub-Saharans and Afro-Caribbeans (P = 0.002 and P = 0.003, respectively). In contrast, in comparison with white Europeans, North Africans had only less frequent arthralgias (P = 0.004). Time to relapse was shorter for black sub-Saharans and Afro-Caribbeans compared with white Europeans [adjusted HR = 1.96 (95% CI: 1.09, 3.51) (P = 0.02)], and did not differ for North Africans. In contrast, overall survival was not significantly different according to ethnicity. Our findings indicated different GPA clinical presentations in white Europeans and sub-Saharans and Afro-Caribbeans, with black patients having more frequent severe granulomatous manifestations. In addition, time to relapse was significantly shorter for black sub-Saharans and Afro-Caribbeans compared with white Europeans.