Anticoagulation: a tenth had a major bleed with long-term warfarin.

Clinical bottom line (level 1b)

  1. A tenth of patients on long-term warfarin treatment had a major bleed at two years.
  2. The risk of a major bleed was increased with:
    • aged 65 or more
    • history of stroke
    • history of gastrointestinal bleed
    • serious comorbid condition
    • atrial fibrillation
Landefeld and Goldman: American Journal of Medicine 1989; 87: 144-151
Expires December 2003

The study

Inception cohort study with objective outcomes, adjusted for confounding factors, not validated in an independent set of patients.

Setting: university hospital, USA

565 patients (aged range 18 to 92 years; mean 61, 54% female) treated with warfarin, or discharged after valvular heart surgery or with mitral valve disease, atrial fibrillation, stroke, transient ischaemic attack, pulmonary embolism, deep vein thrombosis, or other thromboembolism. Patients were included if long-term therapy (planned for at least 10 days, begun during hospitalisation, two weeks before admission, or month after discharge)

Excluded if
  • not treated with warfarin as outpatients


    • Patients were treated with warfarin and anticoagulant therapy was managed by each patient's primary physician.

    Multivariate analysis was used to adjust for confounding factors.

    99.5 followed for median 7 months
    Outcomes studied:
  • major bleeding
  • death from major bleeding

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    major bleeding median 7 months 65/562 12%
    (8.9% to 14%)
    death from major bleeding median 7 months 10/562 1.8%
    (0.69% to 2.9%)

    • Five factors were found to be independently associated with major bleeding:
      • aged 65 or more
      • history of stroke
      • history of gastrointestinal bleed
      • serious comorbid condition
      • atrial fibrillation

    Comments

    1. No relative risks were given for the adjusted risk factors.
    2. Risk factors were determined using a derivation set of 375 randomly chosen patients.
    3. Data such as these have been used to develop clinical prediction guides.

    Citation

    1. Landefeld CS, and Goldman L: Major bleeding in outpatients treated with warfarin: Incidence and prediction by factors known at the start of outpatient therapy. American Journal of Medicine 1989; 87: 144-151
    Contributor: Clare Wotton and Bob Phillips, December 2000
    Reviewer:

    Clinical Question.
    Patient on warfarin
    Intervention or Exposure predicting factors
    Outcome major bleed