title: The presence of multiple prothrombotic risk factors is associated with a higher risk of thrombosis in individuals with anticardiolipin antibodies.
abstract: OBJECTIVE
  To explore the effect of multiple prothrombotic risk factors in individuals with anticardiolipin antibodies (aCL), we evaluated immunologic, coagulation, and genetic prothrombotic abnormalities in a cohort of individuals with different aCL titers.
  
  
  METHODS
  We recruited 87 individuals into 4 categories (normal, low, intermediate, or high) based on their baseline IgG aCL (aCL-IgG) titers. We measured at followup: repeat aCL-IgG, IgM aCL (aCL-IgM), antibodies to beta2-glycoprotein I (anti-beta2-GPI), lupus anticoagulant (LAC) antibodies, protein C, protein S, activated protein C resistance, factor V506 Leiden mutation, methyl tetrahydrofolate reductase (MTHFR) C677T genotype, and prothrombin 20210A gene mutation. Thrombotic events were confirmed.
  
  
  RESULTS
  At recruitment, 20 individuals were negative for aCL-IgG and 67 were positive (22 low, 20 intermediate, and 25 high titer). Twenty of the 87 participants had experienced a previous thrombotic event: 4 in the aCL-IgG negative group and 16 in the aCL-IgG positive group. Among the 87 individuals, the number of those with concomitant prothrombotic risk factors was as follows: 5 had no other prothrombotic risk factors, 32 had 1 risk factor, 24 had 2 risk factors, 10 had 3 risk factors, 10 had 4 risk factors, and 6 had 5 risk factors. Thrombotic events were observed in 20%, 13%, 33%, 10%, 30%, and 50% of these groups, respectively, and the odds ratio associated with a previous thrombotic event was 1.46 per each additional prothrombotic risk factor (95% confidence interval: 1.003-2.134).
  
  
  CONCLUSIONS
  In individuals with positive aCL-IgG, we observed an association between the number of prothrombotic risk factors and history of thrombotic events.
authors.affiliation: Division of Rheumatology, McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada.
authors.forename: Marie
authors.initials: M
authors.lastname: Hudson
authors.forename: Andrée-Laure
authors.initials: AL
authors.lastname: Herr
authors.forename: Joyce
authors.initials: J
authors.lastname: Rauch
authors.forename: Carolyn
authors.initials: C
authors.lastname: Neville
authors.forename: Erika
authors.initials: E
authors.lastname: Chang
authors.forename: Reda
authors.initials: R
authors.lastname: Ibrahim
authors.forename: Chantal
authors.initials: C
authors.lastname: Séguin
authors.forename: Jeannine
authors.initials: J
authors.lastname: Kassis
authors.forename: Lambert
authors.initials: L
authors.lastname: Busque
authors.forename: Paul R
authors.initials: PR
authors.lastname: Fortin
mesh_terms: D000328:Adult; D017153:Antibodies, Anticardiolipin / Q000378:metabolism*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003710:Demography; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D018570:Risk Assessment; D012307:Risk Factors; D013927:Thrombosis / Q000209:etiology*
chemical_list: D017153:Antibodies, Anticardiolipin; D007074:Immunoglobulin G