The Diagnostic and Classification Criteria in Vasculitis (DCVAS) study is an international collaborative project to update classification criteria and develop diagnostic criteria for systemic vasculitis.

Classification criteria were established and widely adopted in 1990; however these criteria need updating as they were developed prior to the wide availability of anti-neutrophil cytoplasm antibody (ANCA) testing and improved imaging techniques. Updated classification criteria will improve the quality of clinical trials and clinical research because patients with specific diseases will able to be reliably grouped.

In the first stages of analysis using data from 1500 patients from the DCVAS study, researchers have developed provisional classification criteria for granulomatosis with polyangiitis (GPA). A final version of the criteria for GPA and criteria for microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (Churg-Strauss, EGPA) are expected by the end of 2017.

Physicians from 133 sites in 33 countries recorded comprehensive clinical data for patients newly-diagnosed with small vessel vasculitis. Each case was reviewed by an expert panel who were asked to provide an independent diagnosis. Only those cases where the submitting diagnosis was agreed by a reviewer or a diagnosis was agreed by two independent reviewers were included in the analysis.

Criteria were developed by comparing data from patients with GPA with data from patients with other types of small vessel vasculitis. The criteria were presented in a preliminary short list of items which contribute to a risk score. The risk score includes a combination of clinical and laboratory items which perform well, but are still at this stage provisional. The presence of cANCA/PR3-ANCA strongly predict GPA, however, where ANCA is not present, additional clinically relevant features may also support the classification of GPA. Researchers will further test the criteria by using other independent sets of data.

The new criteria for GPA should only be used for classification; this means only for patients already diagnosed with a form of vasculitis who are being considered for inclusion in clinical studies.

DCVAS researchers are still working on developing criteria for other vasculitis conditions and will subsequently develop diagnostic criteria using similar methods.

Acknowledgements

The DCVAS study is the largest study conducted in vasculitis to date with over 6000 participants around the world having agreed to include their data in the study. We acknowledge and greatly appreciate the contribution patients and their treating physicians have made to furthering research and the improvement of healthcare in vasculitis.

DCVAS is sponsored by the University of Oxford and is funded by the American College of Rheumatology (ACR), the European League against Rheumatism (EULAR), and the Vasculitis Foundation. DCVAS is supported in the UK by the NIHR Clinical Research Network.