ANCA-ASSOCIATED VASCULITIS (AAV) AND RENAL DISEASE IN A MULTIDISCIPLINARY OUTPATIENT CLINIC IN NORTHERN SPAIN

V. Calvo-Río, S. Al Fazazi, M. Rodriguez Vidriales, C. Escagedo Cagigas, M. Renuncio-García, L. Martín Penagos, D. Prieto-Peña, J. Irure-Ventura, C. Álvarez-Reguera, G. Fernández Fresnedo, E. Rodrigo-Calabia, J. C. Ruiz-San Millán, R. BlancoMarqués de Valdecilla University Hospital, Rheumatology, Santander, Spain Hospital Puerta Del Mar, Rheumatology, Cádiz, Spain Marqués de Valdecilla University Hospital, Nephrology, Santander, Spain Marqués de Valdecilla University Hospital, Immunology, Santander, Spain  Background The severity of clinical features and outcomes in previous series of patients reported with renal disease related to ANCA-associated vasculitis (AAV) vary greatly, probably due to selection bias. Objectives To establish the actual clinical spectrum of renal disease due to AAV in a multidisciplinary outpatient clinic in Northern Spain. Methods Review of 132 patients classified as having AAV between 1994 to 2022; Granulomatosis with polyangiitis (GPA), Microscopic polyangiitis (MPA) or Eosinophilic Granulomatosis polyangiitis (EGPA) was classified according to 2022 ACR/EULAR classification criteria. Results Renal disease was observed in 82 of 132 (62.1%) AAV (38 men/44 women), median age 61.37 years (24-87 years). Table reflects the main clinical findings and outcomes. Renal biopsy was performed in 44 patients (36 patients showing a pauci-immune crescentic glomerulonephritis). The remaining 38 patients were not biopsied due to patient disagreement, mild renal disease or contraindication for biopsy. The most frequent ANCA antibody specificity was MPO (64.6%) followed by PR3 (26.8%) and double positivity in 3 patients (2 MPO and PR3 and 1 MPO and MBG). 43 patients were classified as MPA (52.4%), of those, 18 patients (21.9%) had renal limited vasculitis, 27 GPA (32.9%), and 4 EGPA (4.9%). The rest of the patients had other renal disease (5 microhematuria, 1 amyloidosis, 1 diabetes nephropathy and 1 nephroangiosclerosis). Nephritic syndrome was the most common renal manifestation when the vasculitis was fully established (56.1%). The most frequent therapies used were corticosteroids (68.3%), Cyclophosphamide (46.3%), Azathioprine (35.4%), Rituximab (34.1%) and mycophenolate mofetil (23.2%). After a median follow-up of 6.23 years (7 days-22.9 years) the last median creatinine and glomerular filtration rate (GFR) was 1.4 mg/dl and 43 ml/min, respectively. Renal function worsened compared to baseline in 78.3% of MPO positive and only in 33% of PR3 positive (p=0.005). During the first 12 months follow-up, stabilization or normalization GFR (median GFR at 1 year: 50 ml/min) was observed in 47.1% with no statistical differences among ANCA groups (p=0.303). Renal outcome at the end of follow-up was poorer in MPA than GPA or EGPA (76.3%, 47.4% and 50% respectively worsened GFR from baseline). 16 patients (19.5%) needed dialysis at any moment. Total remission was achieved in 25 patients (30.5%) while relapses were observed in 17 patients (20.7%). Severe infectious was the main severe side-effect, reported in 26 patients (31.7%). Conclusion Most AAV patients had some grade of renal disease during follow-up and almost 20% ended up needing dialysis. Therefore this multi-systemic disease should be managed in a multidisciplinary way to establish an early diagnosis and adequate treatment, limiting chronic disease. References Suppiah R, et al. Annals of the Rheumatic Diseases 2022;81:321-326. Robson, J.C, et al. Arthritis Rheumatol, 74: 393-399. Grayson, P.C., et al. Arthritis Rheumatol, 74: 386-392. Table. Main clinical findings and outcomes of patients with AAV and renal disease. AAV with renal disease (n=82) Renal biopsy; n, (%) 44, (53.66%) ANCA; n, (%)  MPO 53, (64.6%)  PR3 22, (26.8%)  double positivity 3, (3.65%) Diagnosis; n, (%)  MPA 43, (52.4%)  GPA 27, (32.9%)  EGPA 4, (4.9%)  Other diseases 8, (9.8%) Renal involvement; n, (%)  nephritic syndrome 46 (56.1%)  proteinuria > 3.5 g/24h 3 (3.6%)  isolated hematuria 5 (6.1%) Outcome; n, (%)  dialysis 16, (19.5%)  total remission 25, (30.5%)  relapses 17, (20.7%) Abbreviations: ANCA-associated vasculitis (AAV), Granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA) or microscopic polyarteritis (MPA) Acknowledgements: NIL. Disclosure of Interests Vanesa Calvo-Río Speakers bureau: AbbVie, Lilly, MSD, UCB Pharma, Grunenthal and Celgene., Salma Al Fazazi: None declared, Maria Rodriguez Vidriales: None declared, Clara Escagedo Cagigas: None declared, Mónica Renuncio-García: None declared, Luis Martín Penagos: None declared, Diana Prieto-Peña: None declared, Juan Irure-Ventura: None declared, Carmen Álvarez-Reguera: None declared, Gema Fernández Fresnedo: None declared, Emilio Rodrigo-Calabia: None declared, Juan Carlos Ruiz-San Millán: None declared, Ricardo Blanco Speakers bureau: Abbvie, Pfizer, Roche, Bristol-Myers, Janssen, Lilly and MSD., Grant/research support from: Abbvie, MSD and Roche, Keywords: Vasculitis, Kidneys DOI: 10.1136/annrheumdis-2023-eular.5119Citation: , volume 82, supplement 1, year 2023, page 1613Session: Vasculitis - small vessel vasculitis (Publication only)