AB0582 Atherosclerotic risk factors and upper respiratory inflammations of mpo-anca positive anca associated vasculitis

Background Recent studies had proven that the genetic backgrounds of ANCA associated vasculitis (AAV) were dependent on ANCAs. We and other groups had shown the differences between MPO-ANCA positive Granulomatosis with polyangitis (MPO-GPA) and Microscopic polyangitis (MPA) (1–3). It is not clear what determine these two phenotypes. Objectives To elucidate the etiologies of two phenotypes, we compared the backgrounds and comorbidities between MPO-GPA and MPA. Methods Retrospectively we recruited MPO-GPA and MPA patients through the two multi-center cohorts (Cohort A: 2001–2012, Cohort B: 2012–2016). We classified patients with EMEA classification and ANCA. We found 40 MPO-GPA and 126 MPA cases without overlaps. We compared those backgrounds, comorbidities, organ involvements and outcomes. Results The average age of MPO-GPA group was similar to that of MPA (69.1 years old vs 72.1 years old). But MPO-GPA preferentially affected female patients (80.0% vs 52.8%) with lower creatinine levels (1.03mg/dl vs 2.7mg/dl). Two year survivals of MPO-GPA were significantly better than MPA (95.8% vs 73.2%, p=0.0424). Interestingly MPO-GPA patients had less atherosclerotic risk factors, i.e. smoking history (6.3% vs 38.4%), hypertension (10.4% vs 30.5%) and diabetes (12.5% vs 17.9%). Instead these patients had more upper respiratory inflammations (chronic sinusitis, chronic otitis media and allergic rhinitis, 33.3% vs 6.6%) before the disease onset. Conclusions We found that MPA had more atherosclerotic risk factors, and MPO-GPA had more upper respiratory inflammations. These factors may determine MPA or GPA phenotypes in MPO-ANCA positive AAV. References Ono N at al. Characteristics of MPO-ANCA-positive granulomatosis with polyangiitis: a retrospective multi-center study in Japan. Rheumatol Int. 2015 Mar;35(3):555–9. Miloslavsky EM et al. MPO-ANCA-Positive and ANCA-Negative Patients With Granulomatosis With Polyangiitis (Wegener9s): Distinct Patient Subsets. Arthritis Rheumatol. 2016 Dec;68(12):2945–2952. Schirmer JH at al. MPO-ANCA-Positive Granulomatosis With Polyangiitis (Wegener9s) Is a Clinically Distinct Subset of ANCA-Associated Vasculitis: A Retrospective Analysis of 315 Patients From a German Vasculitis Referral Center. Arthritis Rheumatol. 2016 Dec;68(12):2953–2963. Acknowledgements We gratefully acknowledge the work of people who helped to correct patients data. Disclosure of Interest None declared