Revisiting the classification of clinical phenotypes of anti-neutrophil cytoplasmic antibody-associated vasculitis: a cluster analysis
- 8 September 2012
- journal article
- research article
- Published by BMJ in Annals Of The Rheumatic Diseases
- Vol. 72 (6), 1003-1010
- https://doi.org/10.1136/annrheumdis-2012-201750
Abstract
Background Granulomatosis with polyangiitis (Wegener's) (GPA) and microscopic polyangiitis (MPA) are subgroups of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) defined historically by clinical and histological features. GPA and MPA are heterogeneous entities with overlapping phenotypes. To identify novel subgroupings, cluster analysis was used to explore the phenotypic spectrum of AAV. Methods This study used a dataset of patients newly diagnosed as having GPA and MPA enrolled in five clinical trials. One cluster model included nine clinical baseline variables as input variables, and a second cluster model additionally included ANCA specificities. The clustering process involved multiple correspondence analyses followed by hierarchical ascendant cluster analysis. The clinical relevance of the generated clusters was analysed by their summary characteristics and outcomes. Results The analyses involved data for 673 subjects: 396 (59%) with GPA and 277 (41%) with MPA. Both cluster models resulted in five partially redundant clusters of subjects, and the model including ANCA resulted in more pertinent separations. These clusters were named ‘renal AAV with proteinase 3 (PR3)-ANCA’ (40% of subjects), ‘renal AAV without PR3-ANCA’ (32%) and ‘non-renal AAV’ (12%), ‘cardiovascular AAV’ (9%) and ‘gastrointestinal AAV’ (7%). The five clusters had distinct death and relapse rates. On the basis of 4 variables, 651 subjects (97%) could be accurately allocated to 1 of the 5 classes. Conclusions This analysis suggests that AAV encompasses five classes associated with different outcomes. As compared with the traditional GPA–MPA separation, this classification system may better reflect the phenotypic spectrum of AAV.Keywords
This publication has 30 references indexed in Scilit:
- Incidence of malignancy in patients treated for antineutrophil cytoplasm antibody-associated vasculitis: follow-up data from European Vasculitis Study Group clinical trialsAnnals Of The Rheumatic Diseases, 2011
- The Five-Factor Score RevisitedMedicine, 2011
- Long-term patient survival in ANCA-associated vasculitisAnnals Of The Rheumatic Diseases, 2010
- Randomized Trial of Plasma Exchange or High-Dosage Methylprednisolone as Adjunctive Therapy for Severe Renal VasculitisJournal of the American Society of Nephrology, 2007
- Presentation and Outcome of Gastrointestinal Involvement in Systemic Necrotizing VasculitidesMedicine, 2005
- Predicting mortality in systemic Wegener's granulomatosis: A survival analysis based on 93 patientsArthritis Care & Research, 2004
- A Proportional Hazards Model for the Subdistribution of a Competing RiskJournal of the American Statistical Association, 1999
- Nomenclature of Systemic VasculitidesArthritis & Rheumatism, 1994
- Cluster analysis and related techniques in medical researchStatistical Methods in Medical Research, 1992
- The American College of Rheumatology 1990 criteria for the classification of wegener's granulomatosisArthritis & Rheumatism, 1990