AB0696 Clinical characteristics and outcome of patients with granulomatosis with polyangiitis (GPA) according to anca positivity and specificity

Background GPA is a necrotizing granulomatous vasculitis associated with ANCA that usually involves ENT, lung and kidneys. ANCA are mostly directed against proteinase 3 (PR3), although in few cases are directed against myeloperoxidase (MPO) or negative. Objectives To analyse the phenotype, clinical course and outcome of patients with GPA according to ANCA positivity and specificity Methods multicenter retrospective-longitudinal study that included patients diagnosed with AAV between Jan 1995 and Jan 2016 in 21 Hospitals from Spain (REVAS-Study). We analysed the clinical characteristics, treatment and outcome, depending on the ANCA positivity and specificity. Statistical analysis was performed using SPSSvs.20 Results 221 patients with GPA were included:162 with PR3-ANCA, 36 with MPO-ANCA, and 23 with negative-ANCA. The mean-age at disease onset was higher in patients with MPO-ANCA (59.9□16.5 years) than in patients with PR3-ANCA (50.5□16.5) and negative ANCA (48□14.5), p=0.006. Compared to patients with PR3-ANCA, patients with MPO-ANCA presented a lower prevalence of toxic syndrome (42.9% vs. 55.6%, p=0.021), arthralgias (34.3% vs. 59.9%, p=0.008), arthritis (8.6% vs. 26.5%, p=0.026), pulmonary involvement (cavitated/infiltrated nodules, p=0.007 and p=0.05), and anaemia (57.1% vs. 77.8%, p=0.05). Renal disease was less severe in patients with MPO-ANCA (creatinine ≥1.58 mg/dL 14.3% vs. 30.4%,p=0.04). Subglottic stenosis and sensoryneural deafness were more frequent in patients with MPO-ANCA (20% vs. 6.8%, p=0.05% and 34.3% vs. 18%, p=0.03). The mean BVAS at baseline was lower in patients with MPO-ANCA (16.3□8.8) and negative ANCA (12.5□6.7) than in patients with PR3-ANCA (19.6□8.9), p=0.029. Patients with negative ANCA had less frequently toxic syndrome, fever, arthritis, subglottic stenosis, kidney disease, and peripheral neuropathy, and more frequently orbital masses. Disease relapses were less frequent in patients with MPO-ANCA than in patients with PR3-ANCA (37.1% vs. 48.8%, p=0.04), but more frequent than in patients with negative ANCA (20.8%), p=0.002. Patients with MPO-ANCA and negative ANCA received less frequently oral cyclophosphamide. No significant differences were found related to death in patients with MPO-ANCA and PR3-ANCA. Patients with negative ANCA had the lower mortality Conclusions A small percentage of patients with GPA present MPO-ANCA or negative ANCA. In our series, patients with MPO-ANCA were older at the disease onset, presented limited or less severe organic disease than patients with PR3-ANCA, lower percentage of relapses and lower requirement of aggressive therapies. Patients with negative ANCA had the best prognosis. Our findings are similar to those recently published,1 although our patients with MPO-ANCA were older. Classification of GPA patients considering ANCA specificity can improve the treatment stratification and reduce adverse events. Reference [1] Schirmer JH, et al. Myeloperoxidase-antineutrophil-cytoplasmic-antibody (ANCA) positive Granulomatosis with polyangiitis.A clinically distinct subset of ANCA-assocaited vasculitis. Arthritis Rheum2016;68:2953–63 Disclosure of Interest None declared