title: B blood group: A strong risk factor for venous thromboembolism recurrence.
abstract: BACKGROUND
  Non-O blood group patients are at higher risk of first episode of venous thromboembolism (VTE). However, only little is known about the risk of recurrence according to the blood group. In this study, we aimed to determine the impact of ABO blood group on VTE recurrence.
  
  
  METHODS
  We prospectively recruited 106 consecutive patients with a first documented episode of pulmonary embolism (PE). Patients were followed at least 12months after anticoagulation discontinuation. The main endpoint was recurrence of symptomatic VTE.
  
  
  RESULTS
  Data from 100 patients were analyzed. Median follow-up was 28months [24-34.8]. PE was unprovoked in 48 patients. Mean anticoagulation duration was 5.3±2.2months. The rate of VTE recurrence was 12.7 per 100 patient-years (30 recurrences). B blood group patients had a 2.7-fold increased risk of VTE recurrence (95%CI 1.1-6.2, p=0.03). On multivariate analysis, B blood group was the strongest independent predictor of VTE recurrence (Hazard Ratio (HR) 2.6, 95%CI 1.1-6.1, p=0.04). In contrast, A and AB blood groups were not associated with VTE recurrence. VTE recurrences were less frequent in O blood group compared to non-O patients (HR 0.5, 95%CI 0.2-1.1, p=0.09). O blood group women had a 5-fold decreased risk of VTE recurrence (HR 0.2, 95%CI 0.1-0.8, p=0.01).
  
  
  CONCLUSIONS
  Non-O blood groups, beyond being involved in the occurrence of a first VTE event, also contribute to VTE recurrence. B blood group is strongly associated with VTE recurrence, thus high-risk B blood group patients could benefit from long-term anticoagulation therapy after a first VTE event.
authors.affiliation: Cardiology Department, Pasteur University Hospital, CHU de Nice, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Baudouy
authors.affiliation: Cardiology Department, Pasteur University Hospital, CHU de Nice, France. Electronic address: moceri.p@chu-nice.fr.
authors.forename: Pamela
authors.initials: P
authors.lastname: Moceri
authors.affiliation: Cardiology Department, Pasteur University Hospital, CHU de Nice, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Chiche
authors.affiliation: Cardiology Department, Pasteur University Hospital, CHU de Nice, France.
authors.forename: Priscille
authors.initials: P
authors.lastname: Bouvier
authors.affiliation: Cardiology Department, Pasteur University Hospital, CHU de Nice, France.
authors.forename: Elie-Dan
authors.initials: ED
authors.lastname: Schouver
authors.affiliation: Cardiology Department, Pasteur University Hospital, CHU de Nice, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Cerboni
authors.affiliation: Cardiology Department, Pasteur University Hospital, CHU de Nice, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Gibelin
authors.affiliation: Cardiology Department, Pasteur University Hospital, CHU de Nice, France.
authors.forename: Emile
authors.initials: E
authors.lastname: Ferrari
mesh_terms: D000017:ABO Blood-Group System / Q000097:blood*; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D054556:Venous Thromboembolism / Q000097:blood* / Q000188:drug therapy / Q000453:epidemiology / Q000473:pathology
chemical_list: D000017:ABO Blood-Group System; D000925:Anticoagulants
keywords: ABO Blood-Group System; Pulmonary embolism; Venous Thromboembolism