THU0292 THE PERFORMANCE OF THE SUGGESTED EXPANSION OF THE 1990 ACR CRITERIA WITH THE ORIGINAL ACR 1990 CRITERIA IN GIANT CELL ARTERITIS PATIENTS
Authors: P. M. Andel, S. Brådland, V. Haraldstad, H. Bitter, A. Diamantopoulos, G. Haugeberg
Journal: Annals of the Rheumatic Diseases (2020)

Background: The ACR Giant Cell Arteritis (GCA) criteria from 1990 includes items of clinical findings and biopsy results (1). Since that time better imaging modalities as ultrasound (US), magnetic resonance imaging (MRI) and positron emission tomography (PET) have challenged the former gold standard status of biopsy diagnosing GCA (2). In 2017 suggested expansion of the ACR criteria was proposed including these imaging modalities and a more nuanced set of clinical features (3). Objectives: To test the sensitivity of the suggested expanded GCA criteria against the original ACR 1990 criteria in a retrospective cohort of patients diagnosed with GCA. Methods: We included all patients diagnosed with GCA in our rheumatology clinic between 2006 and 2018 in Agder County in Southern Norway. A predefined protocol was used when reviewing the medical records in GCA patients at the time of diagnosis. Data collected included the separate items for the original and the suggested expansion of the ACR 1990 criteria. We calculated the sensitivity of both criteria sets and recorded the frequency and absolute numbers of the single criteria items as shown in table 1. Table 1. Disease features of switch and swap TA patients at 2 nd bDMARD start. Original Criteria N Suggested expansion Criteria n N Criterion 1 Age ≥ 50 yrs 77 Age ≥ 50 yrs 77 77 Criterion 2 New onset of or new type of localized pain in the head 48 New onset of or new type of localized pain in the head 48 61 Visual symptoms 14 Sight loss 2 PMR 22 Constitutional symptoms 2 Tongue claudication 5 Jaw claudication 16 Criterion 3 Abnormal temporal artery palpation tenderness, decreased pulse 26 Abnormal of extracranial arteries tenderness to palpation, decreased pulse 26 30 Bruits over arteries 6 Criterion 4 ESR &gt; 50 mm/h 62 ESR &gt; 50 mm/h 62 72 CRP &gt; 10 mg/l 72 Criterion 5 Abnormal artery biopsy 22/37 Abnormal artery biopsy 22/37 68 US 61/69 MRI 6/10 F-FDG PET 4/4 Results: A total of 77 patients (22 men and 55 Women) with a diagnosis of GCA were identified. Mean age was 69.2 years. The table below shows the absolute number of patients fulfilling the separate criteria for the ACR 1990 and the suggested expansion criteria. Patients were usually not exposed to all submodalities of criterion 5. The denominator for item 5 in the table displays the number of assessments performed for biopsy and the separate imaging modalities. The number of patients fulfilling the original ACR 1990 criteria was 51 (66.2%) and for the suggested expansion criteria 75 (97.4%). All patients fulfilled the age criterion. For the original ACR 1990 criteria, 62.3% met criterion 2, 33.8% criterion 3, 80.5% criterion 4 and 28.6% criterion 5, whereas for the suggested expansion criteria the percentages was 79.2%, 39.0%, 93.5% and 88.3% respectively. Conclusion: The proposed expansion of the ACR 1990 criteria had a much higher sensitivity (97.4%) than the original criteria (66.2%) tested in a clinical cohort of GCA patients. The single most important parameter increasing sensitivity was US examination however also new clinical features and C-reactive protein measurement contributed to increase the sensitivity. References: [1]Hunder GG et al. Arthritis Rheum 1990;33:1122-8 [2]Dejaco C et al. Ann Rheum Dis 2018;77:636-43 [3]Dejaco C et al. Rheumatology 2017;56:505-15. Disclosure of Interests: Peter Michael Andel Grant/research support from: Travel Grant from Vest Agder Legeforening, Norge, Serina Brådland: None declared, Vilde Haraldstad: None declared, Helle Bitter: None declared, Andreas Diamantopoulos: None declared, Glenn Haugeberg: None declared