title: The Association Between Bleeding and the Incidence of Warfarin Discontinuation in Patients with Atrial Fibrillation.
abstract: OBJECTIVE
  While bleeding is a well-known complication of warfarin use and is thought to be a contributory cause of treatment discontinuation, studies quantifying this association are limited. The objective of this study was to quantify the association between bleeding events and subsequent warfarin discontinuation in patients with nonvalvular atrial fibrillation (NVAF).
  
  
  METHODS
  A nested case-control analysis was conducted within a cohort of patients with NVAF newly treated with warfarin. All patients who discontinued warfarin (at least 60 days from last day of warfarin supply) during follow-up were identified as cases and matched with up to 10 controls on age, sex, and duration of follow-up. The index date was defined as the date of warfarin treatment discontinuation of the cases. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of warfarin treatment discontinuation associated with a bleeding event in the 60 days before the index date.
  
  
  RESULTS
  The cohort included 24,243 patients who initiated warfarin treatment, of whom 13,482 discontinued treatment during follow-up (cases). Bleeding was associated with an increased risk of warfarin treatment discontinuation (3.55% vs. 0.85%; OR, 4.31; 95% CI, 3.87-4.81). When including only bleeds as the first listed diagnosis, the unadjusted OR was 4.64 (95% CI, 4.10-5.26), and the adjusted OR was 4.65 (95% CI, 4.10-5.27).
  
  
  CONCLUSIONS
  Bleeding was significantly associated with warfarin discontinuation, and thus, the selection of an effective treatment regimen associated with a lower bleeding rate could be a desirable treatment approach.
authors.affiliation: Global Health Economics and Outcomes Research, Bristol-Myers Squibb, Princeton, NJ, USA.|Global Pharmacovigilance and Epidemiology (GPVE), Bristol-Myers Squibb, Pennington, NJ, USA.
authors.forename: Teresa A
authors.initials: TA
authors.lastname: Simon
authors.affiliation: Global Health Economics and Outcomes Research, Bristol-Myers Squibb, Princeton, NJ, USA.
authors.forename: Xianying
authors.initials: X
authors.lastname: Pan
authors.affiliation: Global Health Economics and Outcomes Research, Bristol-Myers Squibb, Princeton, NJ, USA.
authors.forename: Hugh
authors.initials: H
authors.lastname: Kawabata
authors.affiliation: Global Pharmacovigilance and Epidemiology (GPVE), Bristol-Myers Squibb, Pennington, NJ, USA.
authors.forename: Han-Yao
authors.initials: HY
authors.lastname: Huang
authors.affiliation: Centre for Clinical Epidemiology, Lady Davis Research Institute, Jewish General Hospital, Montreal, QC, Canada.|Department of Oncology, McGill University, Montreal, QC, Canada.
authors.forename: Laurent
authors.initials: L
authors.lastname: Azoulay
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D001281:Atrial Fibrillation / Q000150:complications*; D016022:Case-Control Studies; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D020521:Stroke / Q000209:etiology / Q000517:prevention & control*; D014859:Warfarin / Q000008:administration & dosage* / Q000009:adverse effects; D028761:Withholding Treatment; D055815:Young Adult
chemical_list: D000925:Anticoagulants; D014859:Warfarin
keywords: Atrial fibrillation; Bleeding events; Discontinuation; Hospitalization; Warfarin