Identifying phenotypes of patients with antiphospholipid antibodies: results from a cluster analysis in a large cohort of patients

Abstract Objectives To identify the aggregation of patients with aPL into different subgroups sharing common features in terms of clinical and laboratory phenotypes. Methods We applied a hierarchical cluster analysis from the multiple correspondence analysis to determine subgroups of patients according to clinical and laboratory characteristics in a cohort of subjects with confirmed aPL positivity who presented to our outpatient clinics from 2006 to 2018. Results A total of 486 patients [403 women; age 41.7 years (26)] were included, resulting in five clusters. Cluster 1 (n= 150) presented with thrombotic events (65.3% with venous thrombosis), with triple aPL positivity found in 34.7% of them (the highest rate among the different clusters). All the patients from cluster 2 (n = 91) had a confirmed diagnosis of SLE and the highest rate of anti-dsDNA positivity (91.7%). Cluster 3 included 79 women with pregnancy morbidity. Triple positivity was present in 3.8%, significantly lower when compared with Cluster 1 (34.7% versus 3.8%, P