Anticoagulation: guidelines and consultation reduced bleeds and venous thromboembolism.

Clinical bottom line (level 1b)

  1. Guideline-based consultation reduced anticoagulant-related bleeding in hospitalised patients at increased risk for bleeding (NNT = 6 at 3 months) .
  2. Patients anticoagulated according to the guideline had fewer new or recurrent PEs or DVTs (NNT = 8 at 3 months) .
  3. The effect on major bleeds and mortality was unclear.
Landefeld and Anderson: Annals of Internal Medicine 1992; 116 (10): 829-837
Expires June 2003

The study

Unblinded concealed randomised trial with intention-to-treat
Setting: university teaching hospital, Canada

101 patients (aged mean 72 years, 55% female) treated with warfarin or heparin, and judged to be at moderate (n=60) or high risk (n=41) for bleeding

Excluded if
  • anticoagulant treatment within 30 days of admission
  • treatment for <10 days


    • Control Group: (n = 55, 55 analysed): usual care- nursing and medical care from house staff supervised by an attending physician
    Experimental Group: (n = 46, 46 analysed): usual care plus consultation- guideline-based consultative care with daily visits by a study physician using specific practice guidelines. Guidelines used were based on recommendations made by the ACCP consensus conferences (1986, 1989, 1992). Used for assessing risks and benefits of therapy, alternative treatment, formulation and discussion of specific recommendations for the use, dose and duration of anticoagulants, and daily follow-up.

    100% followed for 3 months
    Outcome notes:
    • minor or major bleeding : major- overt bleeding that led to loss of =2 units of blood in <7 days; minor- other internal bleeding, a drop of =0.06 in haemocrit that led to transfusion of =2 units of blood, or a drop of 20% in haemocrit to <0.30 at discharge

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    minor or major bleeding 3 months 17
    (30.9%)    		 6
    (13.0%)    		 58%
    (2% to 82%)    		 17.9%
    (2.25% to 33.5%)    		 6
    (3 to 44)
    major bleeding 3 months 7
    (12.7%)    		 2
    (4.35%)    		 66%
    (-56% to 93%)    		 8.38%
    (-2.22% to 19.0%)    		 12
    (NNT = 5 to infinity;
    NNH = 45 to infinity)
    new or recurrent PE or DVT 3 months 9
    (16.4%)    		 2
    (4.35%)    		 73%
    (-17% to 94%)    		 12.0%
    (0.60% to 23.4%)    		 8
    (4 to 170)
    death 3 months 6
    (10.9%)    		 6
    (13.0%)    		 -20%
    (-246% to 59%)    		 -2.13%
    (-14.9% to 10.6%)    		 -47
    (NNT = 9 to infinity;
    NNH = 7 to infinity)

  • Potentially reversible factors associated with bleeding:
    • prothrombin time >2 times control
    • activated partial thromboplastin time >3 times baseline
    • insufficient indication for anticoagulation
    • use of non-steroidal anti-inflammatory agents
    • failure to use alternative therapy, eg. vena cava filter

    • Citation

    1. Landefeld CS, and Anderson PA: Guideline-based consultation to prevent anticoagulant-related bleeding. A randomized, controlled trial in a teaching hospital. Annals of Internal Medicine 1992; 116 (10): 829-837
    Search Terms: warfarin in Best Evidence
    Contributor: Chris Ball and Clare Wotton, February 1999
    Reviewer:

    Clinical Question.
    Patient on warfarin/heparin and moderate to high risk of bleeding
    Intervention or Exposure usual care plus consultation
    Comparison usual care
    Outcome bleeding