title: Randomized placebo-controlled study of low-dose warfarin for the prevention of central venous catheter-associated thrombosis in patients with cancer.
abstract: OBJECTIVE
  In this multicenter, randomized, placebo-controlled clinical trial, we studied whether warfarin 1 mg daily reduces the incidence of symptomatic central venous catheter (CVC) -associated thrombosis in patients with cancer.
  
  
  METHODS
  Two hundred fifty-five patients with cancer who required a CVC for at least 7 days were randomly assigned to receive warfarin 1 mg or placebo.
  
  
  RESULTS
  There were 11 (4.3%) symptomatic CVC-associated thromboses among 255 patients, with no difference in the incidence of symptomatic CVC-associated thrombosis between patients taking warfarin 1 mg daily (six of 130 patients; 4.6%) and patients taking placebo (five of 125 patients; 4.0%; hazard ratio, 1.20; 95% CI, 0.37 to 3.94). Warfarin had no effect on CVC life span (84 days v 63 days in control and warfarin groups, respectively; 95% confidence limit, -16 to 55 days; P = .09), and it did not affect the number of premature CVC removals (23.2% v 25.4% in control and warfarin groups, respectively; 95% confidence limit of difference -8.34 to 12.71; P = .68) or the frequency of major bleeding episodes (2% v 0% in control and warfarin groups, respectively; P = .5, Fisher's exact test).
  
  
  CONCLUSIONS
  Symptomatic CVC-associated thrombosis in patients with cancer, although significant, is less common than previously reported. In this study, the administration of warfarin 1 mg daily did not reduce the incidence of symptomatic CVC-associated thrombosis in patients with cancer. However, the low rate of symptomatic CVC-associated thrombosis means that a much larger trial is required to address this issue definitively.
authors.affiliation: Department of Medicine, Dalhousie University and Queen Elizabeth II Health Sciences Centre, Room 417, Bethune Bldg, 1278 Tower Rd, Halifax, Nova Scotia B3H 2Y9, Canada. stephen.couban@cdha.nshealth.ca
authors.forename: Stephen
authors.initials: S
authors.lastname: Couban
authors.forename: Michael
authors.initials: M
authors.lastname: Goodyear
authors.forename: Margot
authors.initials: M
authors.lastname: Burnell
authors.forename: Sean
authors.initials: S
authors.lastname: Dolan
authors.forename: Parveen
authors.initials: P
authors.lastname: Wasi
authors.forename: David
authors.initials: D
authors.lastname: Barnes
authors.forename: Darlene
authors.initials: D
authors.lastname: Macleod
authors.forename: Erica
authors.initials: E
authors.lastname: Burton
authors.forename: Pantelis
authors.initials: P
authors.lastname: Andreou
authors.forename: David R
authors.initials: DR
authors.lastname: Anderson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage*; D002405:Catheterization, Central Venous / Q000009:adverse effects*; D002408:Catheters, Indwelling / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000188:drug therapy; D010919:Placebos; D011859:Radiography; D016896:Treatment Outcome; D020246:Venous Thrombosis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000517:prevention & control*; D014859:Warfarin / Q000008:administration & dosage*
chemical_list: D000925:Anticoagulants; D010919:Placebos; D014859:Warfarin