Background Anca Associated Vasculitis (AAV), are a group of necrotizing primary vascultitis, whith multisistemic manifestation, of unknown etiology. The variants are: Microscopic Polyangiitis (MPA), Granulomatosis with polyangiitis (GPA), Granulomatosis whith Polyangiitis and Eosinophilia (GPE) and AAV limited to one organ. Until now, there are no diagnostic criteria for AAV. Therefore definitions, as Chapell Hill consensus Conference Nomenclature, classification criteria and the physician judgement are used for diagnosis. Currently the DCVAS (Diagnosis and Classification Criteria in Vasculitis) proyect is developing diagnostic criteria for AAV, using data-driven methods. The preliminary DCVAS classification criteria for granulomatosis whith polyangiitis has been recently realesead.
Objectives To evaluate and compare the acuraccy of ACR/EULAR 2017 provisional Classification Criteria for GPA whith the ACR 1990 Classification Criteria In Chilean patients with AAV.
Methods All adult patients (>18 yo) with diagnoses of AAV according to their rheumatologist judgment, from 2000–2016 at the University of Chile, Clinical Hospital (UCCH), were included. Clinical variables of interest were extracted form medical chart and AAV database, wich is kept for these patients at the Rheumatology Section of UCCH. Based on that data, the Classification criteria ACR 1990 and 2017preliminary ACR/EULAR (DCVAS) classification criteria for GPA were applied to each individual. Sensibility, especifity, Likehood ratio (LR +/-), predictive values (PPV/NPV) and accuracy were calculated for both sets of Criteria as compared to Clinical diagnosis
Results 93 patient were included in the study. 59 patients with GPA, 33 with MPA and 1 with GPE (Patients characteristics are described in Table 1). From the 59 patients with GPA according to clinical judgment, 34 fullfilled the ACR 1990 criteria (57,63%) whereas 51 (86,44%) fullfilled the ACR/EULAR 2007 criteria. From the 33 patients diagnosed as having MPA 9 (27,27%) and and 3 (9.09%) fulfilled classification criteria for GPA according to ACR 1990 criteria and 2017 ACR/EULAR preliminary criteria, respectively.The patient with GPE did no classify as GPA by either set of criteria.The values for Sensibility, Espicifity, LR+ LR-, PPV and NPV in our population for both Criteria sets, are described in table 2.
Conclusions In our population, provisional 2017 ACR/EULAR criteria for classificatiόn of GPA have better acurracy than ACR 1990 classification criteria.
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Disclosure of Interest None declared