Pos0864 Newly Diagnose Anca-Associated Vasculitis, Is There Really an Increase in Cases Related to Covid-19 Pandemic? Study in a Single University Hospital

Background: Anti-neutrophil cytoplasmic antibodies (ANCA) associated vasculitis (AAV), affects small and medium-sized vessels. The exact mechanisms leading to an excess production of ANCA are not clear. In healthy individuals, ANCA specific for proteinase (PR3-ANCA) and for myeloperoxidase (MPO-ANCA) are detected in circulation. These findings suggests that ANCA presence is not enough for developing AAV and that further steps are necessary for the onset of autoimmunity1. It has been shown that both Coronavirus disease 2019 (COVID-19) infection and vaccine may trigger AAV2. Objectives: To compare the presence of AAV in new onset ANCA positive tests (+ANCA) in 2019 (COVID-19 pre-pandemic) vs 2021 and 2022 (COVID-19 pandemic). Methods: All ANCA tests performed in 2019, 2021 and 2022 in a referral hospital were reviewed. Patients with new onset +ANCA tests during each year were studied and divided in two groups: +ANCA with AAV and +ANCA without AAV. Diagnosis of underlying AAV was based on ACR/EULAR 2022 criteria. Disease activity and prognosis at diagnosis were assessed with Birmingham Vasculitis Activity Score (BVAS) and Five Factor Score (FFS). ANCA testing was done by chemiluminescence assay using IO-FLASH (Inova, San Diego, CA). Results: We found new +ANCA tests in 46 of 1290 cases (3.6%), 45 of 1434 (3.1%) and 55 of 1687 (3.3%) in 2019, 2021 and 2022 respectively. They were diagnosed with AAV in 13 (28%), 22 (49%) and 14 (25%) cases in 2019, 2021, and 2022, respectively (Figure 1). The proportion was significantly higher in 2021 (p=0.031, Pearson Chi-Square test). The main features of AAV cases are summarized in Table 1. Mean age and sex were similar in pre-COVID (2019) and COVID (2021 and 2022) years. Although AAV severity (BVAS and FFS) were also similar, ANCA levels, proportion of PR3-ANCA, and granulomatosis with polyangiitis (GPA) were higher in AAV patients with new onset in COVID years (p=0.524, p=0.417 and p=0.480). In 2021 and 2022, 75 cases had +ANCA after vaccination or documented COVID-19 infection, with a median of 70 days IQR95%C:28-168 and 134 days IQR 95%CI: 74-202 until +ANCA test in AAV and no AAV cases respectively (p=0.012, Mann-Whitney U test). Conclusion: We observed similar rates of new onset +ANCA test in pre-COVID (2019) and during the COVID pandemic years (2021-2022). There was an increase of new AAV cases in 2021 probably coinciding in addition to COVID-19 pandemic with mass COVID-19 vaccination. No increased disease activity (BVAS) or worse prognosis (FFS) were observed. Also, may be a temporal relation of COVID-19 disease or vaccination with AAV cases during pandemic. REFERENCES: 1 Kronbichler A, et al. Int J Mol Sci. 2020. PMID: 33023023. 2 Irure-Ventura J, et al. iScience. 2022. PMID: 35937087. Acknowledgements: NIL. Disclosure of Interests: Ligia Gabrie: None declared, Fabricio Benavides-Villanueva: None declared, Hector Miguel Ulloa Alvarado: None declared, Mónica Renuncio-García: None declared, Diana Prieto-Peña: None declared, Vanesa Calvo-Río Abbvie, Lilly, Grünenthal, AMGEN, MSD, Novartis, Galápagos, Vifor, GSK and Otsuka, Ricardo Blanco Abbvie, Pfizer, Roche, Bristol-Myers-Squibb, Janssen, Lilly, Novartis, UCB and MSD, Abbvie, MSD and Roche.