SAT0426 Antiphospholipid Syndrome Alliance for Clinical Trials &amp; International Networking (APS Action) Clinical Database and Repository (“Registry”) Cluster Analysis for Identification of Different Clinical Phenotypes Among Antiphospholipid Antibody-Positive Patients
Authors: S. Zuily, D. Wahl, D. Erkan
Journal: Annals of the Rheumatic Diseases (2015)

<h3>Background</h3> APS ACTION "Registry" was created to study the natural course of disease over 10 years in persistently aPL-positive patients with/without other systemic autoimmune diseases. "Cluster analysis (CA)" is a data driven method that can group patients in a way that patients in the same group (cluster) are more similar to each other than to those in other groups. <h3>Objectives</h3> To identify novel clinical phenotypes among aPL-positive patients. <h3>Methods</h3> A web-based data capture system is used to store patient demographics, aPL-related history, and medications. The inclusion criteria are positive aPL based on the Revised Sapporo Classification Criteria at least twice within one year prior to enrollment. CA, using Ward9s minimum-variance hierarchical method, was performed on the baseline characteristics of the first 500 patients. Thirty clinical data points were included in the CA to cover a broad spectrum of aPL-positive patients. To identify differences between clusters, ANOVA and χ<sup>2</sup> test of independence were used. Tests were adjusted for all pairwise comparisons within a row using the Bonferroni correction to identify <i>predominant</i> and <i>discriminant</i> variables (Table). <h3>Results</h3> After excluding missing data, 497 patients from 20 centers were analyzed. Three main exclusive clusters with different combinations of <i>predominant</i> demographic, clinical, and laboratory features were (Table): a) Cluster 1 – female patients with no other autoimmune diseases, but with venous thromboembolism (VTE) and triple-aPL positivity; b) Cluster 2 – female patients with lupus, VTE, aPL-related nephropathy, thrombocytopenia, hemolytic anemia, and positive lupus anticoagulant test; and c) Cluster 3 – older patients with arterial thrombosis, heart valve disease, livedo, skin ulcer, neurological manifestations, and cardiovascular risk factors. <h3>Conclusions</h3> Based on our hierarchical cluster analysis, we identified three different clinical phenotypes of aPL-positive patients discriminated by antiphospholipid antibodies, lupus, or cardiovascular risk factors, respectively. Our results: a) support the heterogeneity of aPL-positive patients; and b) provide a foundation to understand disease mechanisms, create new approaches for APS classification, and ultimately to develop new management approaches. <h3>Acknowledgements</h3> APS ACTION Members (*Top 5 Recruiting Centers): <i>Australia:</i> Sydney (B Giannakopoulos, S Krilis); <i>Brazil:</i> Rio de Janeiro (G de Jesus, R Levy), São Paulo (R Rosa*, D Andrade*); <i>Canada:</i> Quebec (PR Fortin); <i>China:</i> Beijing (Z Zhang); <i>France:</i> Nancy (S Zuily, D Wahl); <i>Greece:</i> Athens (M Tektonidou*); <i>Italy:</i> Brescia (C Nalli, L Andreoli, A Tincani), Milan (CB Chighizola, PL Meroni), Padova (A Banzato*, V Pengo*); <i>Jamaica:</i> Kingston (K De Ceulaer); <i>Japan:</i> Sapporo (T Atsumi); <i>Lebanon:</i> Beirut (I Uthman); <i>Netherlands:</i> Utrecht (RH Derksen, PG de Groot); <i>Spain:</i> Barakaldo (G Ruiz Irastorza*), Barcelona (I Rodriguez-Pinto, G Pons-Estel, R Cervera), Madrid (E Rodriguez); <i>United Kingdom:</i> London (I Mackie, H Cohen; and S Sciascia, ML Bertolaccini, M Cuadrado, M Khamashta); <i>USA:</i> Baltimore (M Petri), Boston (M Barbhaiya), Chapel Hill (R Roubey), Durham (T Ortel), Galveston (E Gonzalez, R Willis), New York City (SR Levine; J Rand; and D Erkan*, J Salmon*, MD Lockshin*), Salt Lake City (W Branch). <h3>Disclosure of Interest</h3> None declared