Cluster Analysis To Explore Clinical Subclassification Of Eosinophilic Granulomatosis With Polyangiitis (Churg–Strauss)

Thomas Neumann¹, Frank Moosig², Augusto Vaglio³, Jochen Zwerina⁴, Renato Alberto Sinico⁵, Wojciech Szczeklik⁶, Paolo Bottero⁷, Phillip Bremer⁸, Andrea Gioffredi⁹, Barbara Sokolowska⁶, Luca Di Toma⁵, Federica Maritati⁹, Julian Großkreutz¹⁰, Claus Kroegel¹¹, Matthieu Resche-Rigon¹² and Alfred Mahr¹³, ¹Jena University Hospital, Internal Medicine III, Jena, Germany, ²Vasculitis Clinic, Klinikum Bad Bramstedt & University Hospital of Schleswig Holstein, Bad Bramstedt, Germany, ³Unit of Nephrology, University Hospital of Parma, Parma, Italy, ⁴Ludwig Bolzmann institut of osteology at the 4th medical departmen, Hanusch Hospital, Vienna, Austria, ⁵Clinical Immunology Unit and Renal Unit, Department of Medicine, Azienda Ospedaliera Ospedale San Carlo Borromeo, Milan, Italy, ⁶Department of Medicine, Jagiellonian University Medical College, Krakow, Poland, ⁷llergy and Clinical Immunology Unit, Magenta Hospital, Magenta, Italy, ⁸University Hospital Schleswig Holstein and Klinikum Bad Bramstedt, Bad Bramstedt, Germany, ⁹Department of Clinical Medicine, Nephrology and Health Sciences, University of Parma, Parma, Italy, ¹⁰Department of Neurology, Jena University-Hospital, Jena, Germany, ¹¹Jena University Hospital, Internal Medicine I, Jena, Germany, ¹²Biostatistics, Hopital Saint-Louis, Paris, France, ¹³Department of Internal Medicine, Hospital Saint-Louis, Paris, France

Meeting: 2013 ACR/ARHP Annual Meeting

Keywords: ANCA, Churg-Strauss syndrome and vasculitis

Session Information

Title: Vasculitis I

Session Type: Abstract Submissions (ACR)

Background/Purpose: Results from descriptive studies of eosinophilic granulomatosis with polyangiitis (EGPA) suggest distinct clinical subclasses that may be determined by anti-neutrophil cytoplasmic antibody (ANCA) status. We used hierarchical cluster analysis to explore whether EGPA could be subclassified.

Methods: The study was based on patients with clinically diagnosed EGPA followed in 6 tertiary referral centers for vasculitis in Germany, Italy and Poland. Clinical data and ANCA results were collected retrospectively on a standardized case report form. A hierarchical cluster analysis (Ward’s method) was performed using the following 12 input variables assessed at diagnosis or at relapse including the main symptoms and organ involvements (general symptoms, arthromuscular, mucocutaneous, ophthalmological, ENT, cardiovascular, gastrointestinal, renal and central nervous system involvement, peripheral neuropathy, non-fixed lung infiltrates) and ANCA positivity. The resulting clusters were described by their most prominent summary characteristics. The distribution of clinical variables was analyzed by ANCA status with chi-square test.

Results: The analyzed dataset included 362 EGPA cases diagnosed between 1984 and 2013. Median age at diagnosis was 50 years and 48% were males; ANCA were detected in 35%. The cluster analysis produced 3 clusters of respectively 158 (cluster 1), 74 (cluster 2) and 130 subjects (cluster 3). They were characterized as follows: cluster 1 by high proportion of renal involvement (43%) and positive ANCA serology (73%); cluster 2 by virtually absent renal involvement (4%) and no ANCA (0%); and cluster 3 by an intermediate phenotype with renal involvement (15%), positive ANCA (9%) and more frequent cardiovascular (57% vs. 33% and 38% for clusters 1 and 2, respectively) and gastrointestinal involvement (44% vs. 22% and 15%). Stratification of the 11 clinical input variables by ANCA status found that ANCA positivity was associated with more frequent arthromuscular involvement (P = 0.045), renal involvement (P < 0.0001), peripheral neuropathy (P = 0.011), constitutional symptoms (P = 0.006) while absence of ANCA was associated with more frequent cardiovascular involvement (P = 0.005).

Conclusion: Cluster analysis of EGPA, although reinforcing the link between ANCA status and renal, peripheral nervous system and cardiovascular involvement, does not suggest that this disease is composed of clearly separated and mutually exclusive subclasses.

Disclosure:

T. Neumann,
None;

F. Moosig,
None;

A. Vaglio,
None;

J. Zwerina,
None;

R. A. Sinico,
None;

W. Szczeklik,
None;

P. Bottero,
None;

P. Bremer,
None;

A. Gioffredi,
None;

B. Sokolowska,
None;

L. Di Toma,
None;

F. Maritati,
None;

J. Großkreutz,
None;

C. Kroegel,
None;

M. Resche-Rigon,
None;

A. Mahr,
None.

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