IgA vasculitis in adults: the performance of the EULAR/PRINTO/PRES classification criteria in adults.

BACKGROUND: In 2010, EULAR/PRINTO/PRES proposed new classification criteria for paediatric IgA vasculitis (IgAV) that have a higher diagnostic sensitivity than the 1990 ACR criteria. These criteria have so far not been evaluated in adults, in whom IgAV is considered as a rare disease. Our main objective was to compare the diagnostic performance of EULAR/PRINTO/PRES and ACR classification criteria in adult IgAV.

METHODS: Adult IgAV cases fulfilling the 2012 revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides (ICHCCNV) definition of IgAV at a secondary/tertiary rheumatology referral centre were critically reviewed in a partially retrospective and partially prospective manner. First, we compared the diagnostic sensitivity of ACR and EULAR/PRINTO/PRES criteria in this group of patients. Second, the diagnostic specificity of ACR and EULAR/PRINTO/PRES was determined by applying these criteria to a control group of patients with other systemic vasculitides.

RESULTS: Between 1 January 2010 and 31 December 2014 350 new cases of systemic vasculitis were identified. IgAV was diagnosed in 129, and other systemic vasculitides in 221 (123 had large, six medium and 92 small vessel vasculitis) cases according to ICHCCNV. The diagnostic sensitivity and specificity of the IgAV EULAR/PRINTO/PRES criteria were 99.2 % (95 % CI 95.4-99.9 %) and 86.0 % (95 % CI 80.7-90.3 %), and of the ACR criteria 86.8 % (95 % CI 79.7-92.1 %) and 81.0 % (95 % CI 75.2-85.9 %), respectively with an inter-criteria agreement of 77.5 % (95 % CI: 70.8-84.1 %).

CONCLUSIONS: In the adult population the EULAR/PRINTO/PRES IgAV classification criteria had a higher sensitivity and specificity than the ACR criteria.