Are the 1990 American College of Rheumatology vasculitis classification criteria still valid?

Abstract

Objectives: Advances in diagnostic techniques have led to better distinction between types of vasculitis, potentially affecting the utility of the 1990 ACR classification criteria for vasculitis. This study tested the performance of these criteria in a contemporary vasculitis cohort.

Methods: The Diagnosis and Classification in Vasculitis Study provided detailed clinical, serological, pathological and radiological data from patients with primary systemic vasculitis and clinical context-specific comparator conditions. Fulfilment of six ACR criteria sets and their diagnostic performance was evaluated in patients with a given type of vasculitis and its comparator conditions.

Results: Data from 1095 patients with primary systemic vasculitis and 415 with comparator conditions were available. For classification, sensitivities and specificities for ACR classification criteria were, respectively, 81.1% and 94.9% for GCA; 73.6% and 98.3% for Takayasu's arteritis; 65.6% and 88.7% for granulomatosis with polyangiitis; 57.0% and 99.8% for eosinophilic granulomatosis with polyangiitis; 40.6% and 87.8% for polyarteritis nodosa; 28.9% and 88.5% for microscopic polyangiitis; and 72.7% and 96.3% for IgA-vasculitis. Overall sensitivity was 67.1%. Of cases identified by their respective criteria, 16.9% also met criteria for other vasculitides. Diagnostic specificity ranged from 64.2 to 98.9%; overall, 113/415 comparators (27.2%) fulfilled at least one of the ACR classification criteria sets.

Conclusion: Since publication of the ACR criteria for vasculitis, the sensitivity for each type of vasculitis, except GCA, has diminished, although the specificities have remained high, highlighting the need for updated classification criteria.

Keywords: Churg–Strauss syndrome; Takayasu’s disease; anti-neutrophil cytoplasm antibody; giant cell arteritis; microscopic polyangiitis; polyarteritis nodosa; vasculitis.

Fig. 1

Study population ^aThe study was promoted at international conferences; all centres willing to participate were invited to take part in the study. At the time of this analysis data had been collected in rheumatology, renal, internal medicine, immunology and neurology centres in a total of 31 countries in Asia, Australasia, Europe, North America and South America. ^bSome comparator patients were used for more than one comparator group. AAV: ANCA-associated vasculitis; DCVAS: Diagnostic and Classification in Vasculitis Study; GPA: granulomatosis with polyangiitis; IgAV: IgA-vasculitis; MPA: microscopic polyangiitis; PSV: primary systemic vasculitis; TAK: Takayasu’s arteritis.

Fig. 2

Accuracy and overlap of the 1990 ACR classification criteria in various forms of vasculitis (A) Patients in DCVAS with one of the forms of primary systemic vasculitis with existing 1990 ACR Criteria (n = 944) that were: classified in accordance with physician’s submitted diagnosis (Correctly Classified), not classified in accordance with physician’s submitted diagnosis (Misclassified), or not classified by any of the ACR criteria sets (Unclassified); overlap between Correctly Classified and Misclassified includes patients who were classified by ACR criteria as having more than one diagnosis (one concordant and another non-concordant with physician’s submitted diagnosis. (B) The number of overlapping diagnoses when ACR 1990 criteria were applied to patients determined by the submitting physician as having a form of small-vessel vasculitis. (C) The number of overlapping diagnoses when ACR 1990 criteria were applied to patients determined by the submitting physician as having a form of large-vessel vasculitis. DCVAS: Diagnostic and Classification Criteria in Vasculitis Study; EGPA: eosinophilic granulomatosis with polyangiitis; GPA: granulomatosis with polyangiitis; PAN: polyarteritis nodosa; TAK: Takayasu’s arteritis.