title: Von Willebrand factor predicts major bleeding and mortality during oral anticoagulant treatment.
abstract: OBJECTIVE
  Oral anticoagulation (OAC), predominantly with warfarin, is an effective treatment to prevent thromboembolic events. Serious bleeding is a frequent and feared treatment complication. In this longitudinal cohort study of OAC-treated patients, we aimed to evaluate the relationship between von Willebrand factor (VWF) levels and risk of bleeding complications, cardiovascular mortality and all-cause mortality.
  
  
  RESULTS
  A total of 719 patients receiving warfarin treatment were observed for a mean duration of 4.2 years. All bleeding complications causing hospitalization were registered and classified into clinically relevant bleeding (CRB) and major bleeding. Ischaemic stroke, peripheral arterial embolism, myocardial infarction, and death were also recorded. We identified 113 cases of CRB and 73 of major bleeding. In total, 161 deaths occurred during follow-up with cardiovascular disease identified as the cause of death in 110 patients. Patients in the highest tertile of VWF had a significantly increased risk of bleeding complications: hazard ratio (HR) 2.53 (95% CI 1.41-4.56) for major bleeding and HR 2.19 (95% CI 1.38-3.48) for CRB. VWF, expressed either in tertiles or as a continuous variable, showed a significant association with cardiovascular mortality (HR 1.68, 95% CI 1.40-2.01) and all-cause mortality (HR 1.77, 95% CI 1.52-2.05). In multivariate Cox regression analysis, the findings remained significant after adjusting for age, high-sensitivity C-reactive protein and creatinine.
  
  
  CONCLUSIONS
  Patients with high levels of VWF had an increased risk of bleeding complications, cardiovascular mortality and all-cause mortality during OAC treatment. Our findings imply that the use of VWF as a risk marker for thromboembolic events is complicated by the association of VWF with bleeding complications.
authors.affiliation: Department of Public Health and Clinical Medicine, Umeå University, Umeå. Marcus.lind@vll.se
authors.forename: M
authors.initials: M
authors.lastname: Lind
authors.forename: K
authors.initials: K
authors.lastname: Boman
authors.forename: L
authors.initials: L
authors.lastname: Johansson
authors.forename: T K
authors.initials: TK
authors.lastname: Nilsson
authors.forename: L Slunga
authors.initials: LS
authors.lastname: Järvholm
authors.forename: J-H
authors.initials: JH
authors.lastname: Jansson
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects*; D002318:Cardiovascular Diseases / Q000401:mortality; D002423:Cause of Death; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006470:Hemorrhage / Q000097:blood / Q000139:chemically induced* / Q000401:mortality*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012307:Risk Factors; D014859:Warfarin / Q000008:administration & dosage / Q000009:adverse effects*; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D000925:Anticoagulants; D014841:von Willebrand Factor; D014859:Warfarin