Effects of Clinicopathologic Classification in ANCA-Associated Vasculitis

Among patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), clinicopathologic classification appears to be the strongest criterion for distinguishing among homogeneous prognoses of AAV, according to the results of a retrospective, single-center study published in Rheumatology.

The investigators sought to retrospectively assess the effect of AAV reclassification based on clinicopathologic criteria and/or ANCA specificity. Consecutive patients who had ever tested positive for anti-proteinase 3 (PR3) or anti-myeloperoxidase (MPO)-ANCA during the course of their disease were included in the analysis. Demographic, laboratory, and clinical data were compiled retrospectively and examined based on anti-PR3 vs anti-MPO-ANCA positivity.

A total of 150 patients with AAV were included in the study, among whom 63% had granulomatosis with polyangiitis (GPA) and 37% had microscopic polyangiitis (MPA). Additionally, 58% of patients had anti-PR3 ANCA and 42% had anti-MPO-ANCA. The median participant age at diagnosis was 62 years. Overall, 67 patients were women and 83 were men. Clinical presentations of the participants primarily included constitutional symptoms, along with renal, pulmonary, rheumatologic, and ear, nose, or throat involvement. Participants’ median Birmingham Vasculitis Activity Score (BVAS) score was 18.

Patients with GPA exhibited significantly worse relapse-free survival but better renal survival (P <.001 and P =.021, respectively) compared with patients with MPA. Overall, relapse-free, and renal survival rates were similar between patients with anti-PR3 and those with anti-MPO (P =.35, P =.17, and P =.15, respectively). The prognosis was identical between patients with anti-MPO MPA and those with anti-PR3 MPA (P =.33, P =.19, and P =.65, respectively), as well as between patients with anti-MPO GPA and those with anti-PR3 GPA (P= .06, P= .99, and P= .64, respectively). In patients with anti-PR3 and those with anti-MPO GPA, no differences in clinical manifestations of disease or BVAS scores were noted.

The investigators concluded that the relevance of ANCAs for subdividing AAVs appears to be less useful and meaningful than the clinicopathologic classification, since the distinction between GPA and MPA is better in predicting prognostic patterns of disease. Thus, although combining serologic and clinicopathologic classifications does not seem to bring any additional value to clinical practice, multicenter studies are warranted to confirm this tendency.

Reference

Deshayes S, Martin Silva N, Khoy K, et al. Clinical impact of subgrouping ANCA-associated vasculitis according to antibody specificity beyond the clinicopathological classification [published online February 25, 2019]. Rheumatology (Oxford). doi:10.1093/rheumatology/kez016