ACR, EULAR preview release of new classification criteria for vasculitis

The ACR and the European Alliance of Associations for Rheumatology (EULAR) previewed new classification criteria for vasculitis at ACR Convergence 2021. It’s the ACR’s first update to the classification criteria for vasculitis since 1990.

“We know that things have changed over time in the management of these diseases,” said Peter Grayson, MD, MSc, of the National Institutes of Health. “As such, there are now limitations of the 1990 ACR classification criteria — primarily because they were developed before widespread use of advanced vascular imaging modalities.”

Dr. Grayson and Raashid Luqmani, MBBS, DM, FRCP, discussed the updated criteria during the session New ACR/EULAR Classification Criteria for Vasculitis on Tuesday, Nov. 9. The session can be viewed on demand by registered meeting participants through March 11, 2022.

Dr. Grayson discussed the methodology used to establish the new criteria, noting that the criteria are meant for classification and not diagnosis. He also previewed the criteria for large-vessel vasculitis, which are under review by ACR/EULAR committees and are still considered draft criteria.

The draft criteria for giant-cell vasculitis include the requirement that patients must be at least 50 years of age at diagnosis. Also included are weighted clinical criteria such as scalp tenderness or sudden visual loss. Weighted lab criteria include positive temporal artery biopsy or halo sign on temporal artery ultrasound. A sum score of six or greater is needed for giant-cell arteritis classification.

“When we applied these criteria to a validation data set, performance characteristics were excellent,” Dr. Grayson said. “Sensitivity was 87% and specificity was 95%. They outperformed the 1990 criteria.”

For Takayasu arteritis, the draft criteria specify that patients must be 60 years of age or younger and have evidence of vasculitis on imaging. Weighted clinical criteria include female sex, angina or ischemic cardiac pain, and reduced pulse in upper extremity. Imaging criteria include weighted scores dependent on the number of affected arteries involved, or symmetric involvement of paired arteries. A score of five or higher is needed for Takayasu arteritis classification. The new criteria had a sensitivity of 94% and a specificity of 99%, Dr. Grayson noted.

“These newer criteria have heralded the incorporation of modern imaging into our practice. I think this is one of the major advancements of the criteria,” he said.

Dr. Luqmani, Professor Rheumatology at the University of Oxford in the United Kingdom, presented the criteria for anti-neutrophilic cytoplasmic autoantibody (ANCA)-associated vasculitis, which have been endorsed by the ACR/EULAR and have been accepted for publication. After discussing methodology, he reviewed the classification criteria for granulomatosis with polyangiitis, microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis.

For granulomatosis with polyangiitis, weighted clinical criteria include upper airway involvement, cartilaginous involvement, or hearing loss. The most important lab is a positive test for PR3 ANCA, said Dr. Luqmani, adding that a score of five or greater is needed for classification of granulomatosis with polyangiitis. Using this cutoff, the criteria had a sensitivity of 92% and specificity of 94%, he said.

The most important clinical criterion for microscopic polyangiitis is the absence of upper airway involvement, he noted. Important lab criteria include the presence of MPO ANCA — the most dominant criterion — and the absence of PR3 ANCA and eosinophilia. A score of five or higher is needed for classification of microscopic polyangiitis. At this cutoff, the sensitivity of the criteria was 91% and specificity was 94%, he said.

Clinical criteria for eosinophilic granulomatosis with polyangiitis include obstructive airway disease, nasal polyps, and mononeuritis multiplex. The presence of eosinophilia is the most important lab criterion. The presence of PR3 ANCA should push a clinician away from the classification of eosinophilic granulomatosis with polyangiitis, he said, and a score of six or greater is needed for classification. The criteria had a sensitivity of 85% and specificity of 99% at that threshold.

“We are hoping that further validation of these criteria will be undertaken either by completely independent cohorts or in collaboration with [us],” Dr. Luqmani said. “We are hoping that new studies and new trials of vasculitis will incorporate these criteria.”