Methods: Patients with vasculitis or comparator diseases were recruited into an international cohort. The study proceeded in five phases: i) Identification of candidate criteria items using consensus methodology; ii) Prospective collection of candidate items present at the time of diagnosis; iii) Data-driven reduction of candidate items; iv) Expert panel review of cases to define the reference diagnosis; v) Derivation of a points-based risk score for disease classification in a development set using lasso logistic regression with subsequent validation of performance characteristics in an independent set of cases and comparators.
Results: The development set for EGPA consisted of 107 cases of EGPA and 450 comparators. The validation set consisted of an additional 119 cases of EGPA and 437 comparators. From 91 candidate items, regression analysis identified 11 items for EPGA, seven of which were retained. The weighting of final criteria items was: i) Maximum eosinophil count ≥ 1x109/L (+5), ii) Obstructive airway disease (+3), iii) Nasal polyps (+3), iv) cANCA or anti-PR3 ANCA positivity (-3), v) Extravascular eosinophilic predominant inflammation (+2), vi) Mononeuritis multiplex/motor neuropathy not due to radiculopathy (+1), and vii) Hematuria (-1). After excluding mimics of vasculitis, a patient with a diagnosis of small- or medium-vessel vasculitis could be classified as EGPA with a cumulative score of ≥ 6 points. When these criteria were tested in the validation dataset, the sensitivity was 85% (95% confidence interval [95% CI] 77-91%) and the specificity was 99% (95% CI 98-100%).
Conclusion: The 2020 ACR-EULAR EGPA Classification Criteria demonstrate strong performance characteristics and are validated for use in research.
|Journal||Annals of the Rheumatic Diseases|
|Publication status||Accepted/In press - 4 Nov 2021|
- eosinophilic granulomatosis with polyangiitis
- anti-neutrophil cytoplasm antibody